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Saturday, December 17, 2016

KTU Previous Questions with answers of Computing and Problem Solving

KTU Previous Questions with answers of Computing and Problem Solving

KTU Previous Questions with answers of Computing and Problem Solving

Reg. No:………….                                                        Name…………………..
Course Code: BE 101-05
Max Marks: 100                                                                                       Duration:3 hrs
Answer all questions, each question carries 4 marks (40 marks)

1.       a). Name any 3 Optical input devices.
bar code readers, image scanners, optical character recognition
b). Name the different I/O ports used in a computer.
The Universal Serial Bus (USB) port is the most versatile interface used on modern computers. USB ports can be used to connect mice, keyboards, printers, scanners, Cameras, external hard drives, network switches, and more.
The DVI port is used for video on newer monitors.
Network/Ethernet (RJ-45)
The port used for networking on most modern computers is typically referred to as an Ethernet port,but may also be called a RJ-45 jack, network port, or Cat5 part.
c). Define System software with an example.
System software is a type of computer program that is designed to run a computer’s hardware and application programs. If we think of the computer system as a layered model, the system software is the interface between the hardware and user applications.
Eg: Microsoft Windows ,Linux, Unix, Mac OSX,DOS
2. Write a notes on buses.
A bus, in computing, is a set of physical connections (cables, printed circuits, etc.) which can be shared by multiple hardware components in order to communicate with one another.
–>The address bus (sometimes called the memory bus) transports memory addresses which the processor wants to access in order to read or write data.
It is a unidirectional bus.
–>The data bus transfers instructions coming from or going to the processor. It is a bidirectional bus.
The control bus (or command bus) transports orders and synchonisation signals coming from the control unit and travelling to all other hardware components.
–> It is a bidirectional bus, as it also transmits response signals from the hardware.
3. Draw the flow chart to find out the greatest of three numbers. (2)

Flow chart for finding greatest from three numbers

4.   Differentiate between top down and bottom up problem solving strategies (2)
Top-down Approach
A top-down approach (also known as stepwise design) is essentially the breaking down of a system to gain insight into the sub-systems that make it up. In a top-down approach an overview of the system is formulated, specifying but not detailing any first-level subsystems.
topdown – of an approach to a problem that begins at the highest conceptual leveland works down to the details; “a top-down analysis might begin by looking at macro-economic trends”; “top-down programming”
  • Start from given data or observations, derive other data or observations.
  • Use derived data together with given data to derived more data.
  • Eventually, the desired conclusions can be reached.
Bottom-up Approach
Bottom-up processing as an approach wherein there is a progression from the individual elements to the whole.
An approach to a problem that begins with details and works up to thehighest conceptual level; “bottom-up parser”; “a bottom-up model of the reading process”
  • The bottom-up approach helps thinking because the objective is clear.
  • The top-down approach is effective for doing numerical computation from given data.
  • Alternating between the two approaches is an effective strategy for thinking.
Drawing the data-flow diagrams while solving problem helps thinking by clearly identifying the given data, derived data, and desired objectives.
5.Write an algorithm to compute 1-x^2/2!+ x^4/4!- x^6/6!+……..n terms..(2)
Step 1: Start
Step 2: Read x, n values as integers
Step 3: Set i = 2, s = 1, pwr = 1, nr = 1
Step 4: Convert x1 into degrees
Step 5: Assign x1 as sum
Step 6: while (i <= n)
pwr ← pwr + 2;
dr ← dr * pwr * (pwr – 1);
sum ← sum + (nr DIV dr) * s;
s ← s * (-1);
nr ← nr * x1 * x1;
i ← i + 2;
Step 7: Print sum
Step 8: Stop

6.which of the following is a valid variable name in python ? (1)
a) i) 12xyz ii) break iii)A_123 iv) A?B?C
b)Evaluate the expression x**y**z given x=2,y=3,z=2     (1)
2**3**2 = 64
c) Predict the output of following code: (1)
            for i in range (10,-1,-2);
              print i
7.write a python program to find the sum of all even terms in a group of n numbers entered by user. (3)
beg = 0
end = 0
sum = 0
n = 0
print “Enter Starting Number:”,
beg = input()
print “Enter Ending Number:”,
end = input()
n = beg
if ( (n  % 2) == 1):
n += 1
print “Adding Numbers : “,
while(n <= end):
print n,
sum += n
n += 2
print “\nThe result is: “, sum
8. Show how you will use the cosine() and log () functions in your program with the help of an example. (2)
math.log(x,[ base])
With one argument, return the natural logarithm of x (to base e).
With two arguments, return the logarithm of x to the given base, calculated as log
Return the natural logarithm of 1+x (base e). The result is calculated in a way which is
accurate for x near zero.
Return the base-10 logarithm of x. This is usually more accurate than log(x, 10).
Return the cosine of x radians.
9.What will be the output of this program? Briefly explain the working of this code.
Def check(x,y):
If y ==0;
Print ‘error’
Return x/y
a,b =10,5
Print check(a,b)
In the above program  check (a,b) is  passes check  two values: 10 and 5. The function check receives copies of these values and accesses them by the identifiers: x  and y. value of y is 5 so control passes to else part and return 10/5 = 2.so the answer is 2.
10.Write a Python program to compute the nth Fibonacci number . Use a recursive function for the implementation.
# Python program to display the n-th fibonacci number using recursive functions

def recur_fibo(n):
“””Recursive function to
print Fibonacci number”””
if n <= 1:
return n
return(recur_fibo(n-1) + recur_fibo(n-2))
# take input from the user
nterms = int(input(“enter the value of ‘N’ “))
# check if the number of terms is valid
if nterms <= 0:
print(“Plese enter a positive integer”)
for i in range(nterms):
f= recur_fibo(i)
print(“The nth fibonacci number”,f)
11.Let fruit =’apples’ be a string. What will be the output of the following expressions: (2)
i)Len(s1) ii) s1[0:4] iii) s1[6]  iv) s1[-4]
i) len(s1)=6
ii) s1[0:4]=apple
iii) s1[6]=s
iv) s1[-4]=p
12.Let data represent the list [‘circle’,’square’,’triangle’]. Write the expression for following operations: (3)
i) Replace the value ‘circle’ with ‘ellipse’
ii) Add a new value’rectangle’ top end of list
iii) Remove the value ‘square’ and ‘triangle’ from list

i) list[0] = ‘ellipse’
ii) append(‘rectangle’)
iii) list.remove(‘square’)
iv) remove(‘triangle’)
13.Let Farm={‘Sheep’:5,’cows’:2,’goats’:10} be a dictionary . write the statements for following operations. (3)
i)To add the key value pair (Ducks’:8)
ii)to display the number of items in the dictionary.
iii)to remove the key value pair (cows’:2)
i) farm[‘Ducks’] =8
ii) len[farm]
iii)del farm[‘cows’]
14.Write the syntax for opening a file in python. Give one example. (2)
To open a file for writing use the built-i open() function. open() returns a
file object, and is most commonly used with two arguments.
The syntax is:
file_object = open(filename, mode) where file_object is the variable to put thefile object.
The second argument describes the way in which the file will be used.
open() returns a file object, and is most commonly used with two arguments: open(filename, mode).
>>> f = open(‘workfile’, ‘w’)
>>> print f
<open file ‘workfile’, mode ‘w’ at 80a0960>
The first argument is a string containing the filename. The second argument is another string containing a few characters describing the way in which the file will be used.mode can be ‘r’ when the file will only be read, ‘w’ for only writing (an existing file with the same name will be erased), and ‘a’ opens the file for appending; any data written to the file is automatically added to the end. ‘r+’ opens the file for bothreading and writing. The mode argument is optional; ‘r’ will be assumed if it’s omitted.

15.what do you mean by pickling in python? Explain its significance with the help of example.   (3)
pickling is used for serializing and de-serializing a Python object structure. Anyobject in python can be pickled so that it can be saved on disk. What pickle does is thatit “serialises” the object first before writing it to file. Pickling is a way to convert a python object (list, dict, etc.) into a character stream. The idea is that this characterstream contains all the information necessary to reconstruct the object in another
python script.
import pickle
pickle has two main methods. The first one is dump, which dumps an object to a file
object and the second one is load, which loads an object from a file object.
import pickle
a = [‘test value’,’test value 2′,’test value 3′]
[‘test value’,’test value 2′,’test value 3′]
file_Name = “testfile”
# open the file for writing
fileObject = open(file_Name,’wb’)
# this writes the object a to the
# file named ‘testfile’

# here we close the fileObject
# we open the file for reading
fileObject = open(file_Name,’r’)
# load the object from the file into var b
b = pickle.load(fileObject)
[‘test value’,’test value 2′,’test value 3′]

The pickle module keeps track of the objects it has already serialized, so that laterreferences to the same object won’t be serialized again
pickle can save and restore class instances transparently, however the class
definition must be importable and live in the same module as when the object was
16.When does an exception occur during program execution? How are
exception handled in python? Explain with Examples.  (3)
An exception is an event, which occurs during the execution of a
program that disrupts the normal flow of the program’s instructions. In general, when a Python script encounters a situation that it cannot cope with, it raises an eception. An exception is a Python object that represents an error.When a Python script raises an exception, it must either handle the exception immediately otherwise it terminates and quits.
Handling an exception
If you have some suspicious code that may raise an exception, you can defend your
program by placing the suspicious code in a try: block. After the try: block, include an except: statement, followed by a block of code which handles the problem as
elegantly as possible.
Here is simple syntax of try….except…else blocks −
operations here;
except ExceptionI:
If there is ExceptionI, then execute this block.
except ExceptionII:
If there is ExceptionII, then execute this block.
If there is no exception then execute this block.
KTU Previous Questions with answers of Computing and Problem Solving
(Answer any 4 complete questions each having 8 marks)
17.(a) Draw and Explain instruction execution cycle in a computer.
The first step the CPU carries out is to fetch some data and instructions (program) from main memory then store them in its own internal temporary memory areas. These memory areas are called ‘registers’. fetch decode execute cycle
This is called the ‘fetch’ part of the cycle.
For this to happen, the CPU makes use of a vital hardware path called the ‘address bus’.
The CPU places the address of the next item to be fetched on to the address bus.
Data from this address then moves from main memory into the CPU by travelling along another hardware path called the ‘data bus’.
The next step is for the CPU to make sense of the instruction it has just fetched.
This process is called ‘decode’.
The CPU is designed to understand a specific set of commands. These are called the ‘instruction set’ of the CPU. Each make of CPU has a different instruction set.
The CPU decodes the instruction and prepares various areas within the chip in readiness of the next step.
This is the part of the cycle when data processing actually takes place. The instruction is carried out upon the data (executed). The result of this processing is stored in yet another register.
Once the execute stage is complete, the CPU sets itself up to begin another cycle once more.

b) Write notes on OMR,MICR, and OCR devices. (4)
MICR (Magnetic Ink Character Recognition):
Used by banks to read numbers written on cheque.
Special purpose machine reads character made of ink containing magnetized particles.
OCR (Optical Character recognition):
Special preprinted characters that can be read by light source and changed into machine readable form.
Used in department stores to read retail price tags by reflecting light.
OMR (Optical Mark Recognition):
An OMR device senses the presence or absence of a mark such as pencil mark.
Used to calculate or store multiple choice tests.
OMR is a system of reading lines or ‘marks’ which have been made in exactly the right positions on a card or document.
  • The documents to be read have empty boxes to take the marks. These have been pre-printed on to the documents together with information telling the user what to do. The person preparing the data makes pencil or ink marks in the appropriate boxes.
  • The data to be input has to be simple because the user can only make marks and cannot write any information.
APPLICATION: of mark reading
  • A multiple choice question paper
The answer sheets are sent to the examining board and are marked by a computer with an optical mark reader.
ADVANTAGES: of using marks
  • Fewer mistakes are made by machines reading marks than are made reading handwritten characters.
  • Data can be prepared without any special equipment.
  • Data can be prepared where it is collected, e.g. a market researcher can mark a questionnaire while asking people questions in the street.
DISADVANTAGES: of using marks
  • Documents for mark readers are complicated to design. If an item has several values, then the form has to have a different box to mark for each possible value.
  • It is difficult for a computer to check marked data.
  • The person putting the marks on the document has to follow the instructions precisely.

Optical Character Recognition (OCR)
An optical character reader can recognise characters from their shape. As with OMR, light is reflected from the paper and from the ink. In OCR however the reader has to work out what the characters are.
Scanners were originally designed to scan pictures but they can also be used to read text. This system relies on sophisticated OCR software in the computer.
The following types of character can be recognised by scanners and OCR readers.
  • Handwritten characters
  • Printed characters
  • Charity fund donations
Names and addresses of prospective donors are pre-printed on donation forms. The forms are sent to the donors. Each donor sends back a form with some money. The date and amount given are carefully hand printed on the form by an operator. An OCR reader reads the name, the date and the amount. The computer then uses the information to update the donor file and the accounts.
DISADVANTAGES: of using marks
  • Documents for mark readers are complicated to design. If an item has several values, then the form has to have a different box to mark for each possible value.
  • It is difficult for a computer to check marked data.
  • The person putting the marks on the document has to follow the instructions precisely.
Optical Character Recognition (OCR)
An optical character reader can recognise characters from their shape. As with OMR, light is reflected from the paper and from the ink. In OCR however the reader has to work out what the characters are.
Charity fund donations
Names and addresses of prospective donors are pre-printed on donation forms. The forms are sent to the donors. Each donor sends back a form with some money. The date and amount given are carefully hand printed on the form by an operator. An OCR reader reads the name, the date and the amount. The computer then uses the information to update the donor file and the accounts.
  • Different printed fonts can be used (the MICR font is fixed).
  • OCR usually accepts hand printing and normal type.
Over OMR
The documents do not have to be designed so precisely for OCR.
Over other media
  • The data for OCR can be read and checked by people.
  • Written data and printed data can be read at the same time.
  • Documents can be read directly into a computer without any typing, e.g. documents received by fax, old books, etc.
OCR systems often fail to recognise characters – particularly if they are handwritten or in unusual fonts.

Magnetic Ink Character Recognition (MICR)
An MICR reader recognises characters formed from magnetic ink. As the document passes into the reader the ink is magnetised and the characters are recognised by the strength of the magnetism.
Bank cheques
The major British banks all use MICR to encode along the bottom of cheques the following information:
  • the cheque number
  • the branch number of the bank
  • the customer’s account number.
This information is printed on the cheques before they are issued to the customer.
The customer then writes a cheque and pays someone with it. This person pays it into a bank and it is sent to a clearing house. Here the amount of money is added to the bottom of the cheque in magnetic ink using an MICR encoder. The cheque can then be sorted automatically and sent back to the bank of the original customer. The money is then deducted from his or her account.
  • MICR is difficult to forge.
  • Documents can still be read when folded, written on, etc.
  • MICR readers and encoders are very expensive.
  • The system can only accept a few different characters.
18.give the algorithm and flow chart for finding the largest and smallest numbers in a given list of N numbers(8)

Problem: Given a list of positive numbers, return the largest number on the list.
Inputs: A list L of positive numbers
Outputs: A number n, which will be the largest number and smallest of the list.
  1. Set maxto 0 min to 0
  2. For each number xin the list L, compare it to max. If x is larger, set max to x.
  3. For each number xin the list L, compare it to min. If x is smaller, set min to x.
  4. maxis now set to the largest number in the list.
  5. minis now set to the smallest number in the list.
An implementation in Python:
deffind_max (L):
min = 0
return min
a) Differentiate between break and continue statement with proper examples.  (3)

The break statement, like in C, breaks out of the smallest enclosing for or while loop.
Loop statements may have an else clause; it is executed when the loop terminates through exhaustion of the list (with for) or when the condition becomes false (with while), but not when the loop is terminated by a break statement. This is exemplified by the following loop, which searches for prime numbers:
>>>for n inrange(2, 10):
… for x inrange(2, n):
… if n % x ==0:
… print n, ‘equals’, x, ‘*’, n/x
… break
… else:
… # loop fell through without finding a factor
… print n, ‘is a prime number’

The continue statement in Python returns the control to the beginning of the while loop. The continuestatement rejects all the remaining statements in the current iteration of the loop and moves the control back to the top of the loop.
The continue statement can be used in both while and for loops

>>>for num inrange(2, 10):
… if num %2==0:
… print“Found an even number”, num
… continue
… print“Found a number”, num
 b) Write a python program to display all amstrong numbers in a given range.(5)

# take input from the user
upper = int(input(“Enter upper range: “))

for num in range(0,upper + 1):
# initialize sum
sum = 0

# find the sum of the cube of each digit
temp = num
while temp >0:
digit = temp % 10
sum += digit ** 3
temp //= 10

if num == sum:

20 a) Write a python program to count the number of zeroes and negative terms in a given set of n numbers.   (4)

num_array = list ()
num = raw_input(“Enter how many elements you want:”)
count_zero = 0
count_neg = 0
print’Enter numbers in array: ‘
for i in range(int(num)):
n = raw_input(“num :”)
num_array.append (int(n))
if num_array[i] = 0
count_zero = count_zero + 1
elif num_array[i] < 0
count_neg = count_neg + 1
print (“The number of zeroes”, count_zeo)
print (“The number of negatives is”, count_neg)

b)Write a Python program to find Sum of Digits of a Number using Recursion (4)
# Python Program to find Sum of Digits of a Number using Recursion

Sum = 0
def Sum_Of_Digits(Number):
global Sum
if(Number > 0):
Reminder = Number % 10
Sum = Sum + Reminder
Sum_Of_Digits(Number //10)
return Sum

Number = int(input(“Please Enter any Number: “))
Sum = Sum_Of_Digits(Number)
print(“\n Sum of the digits of Given Number = %d” %Sum)
a) Why do we need functions ? What are the advantages of using a function?(3)
A common usage of functions in computer languages is to implement mathematical functions. Such a function is computing one or more results, which are entirely determined by the parameters passed to it.
In the most general sense, a function is a structuring element in programming languages to group a set of statements so they can be utilized more than once in a program. The only way to accomplish this without functions would be to reuse code by copying it and adapt it to its different context. Using functions usually enhances the comprehensibility and quality of the program. It also lowers the cost for development and maintenance of the software.
Functions are known under various names in programming languages, e.g. as subroutines, routines, procedures, methods, or subprograms.
A function in Python is defined by a def statement. The general syntax looks like this:
def function-name(Parameter list):
statements, i.e. the function body
The parameter list consists of none or more parameters. Parameters are called arguments, if the function is called. The function body consists of indented statements. The function body gets executed every time the function is called.
Parameter can be mandatory or optional. The optional parameters (zero or more) must follow the mandatory parameters.
Function bodies can contain one or more return statement. They can be situated anywhere in the function body. A return statement ends the execution of the function call and “returns” the result, i.e. the value of the expression following the return keyword, to the caller. If the return statement is without an expression, the special value None is returned. If there is no return statement in the function code, the function ends, when the control flow reaches the end of the function body and the value value will be returned.

b) Write a python program to simulate a menu driven calculator with Addition, subtraction, multiplication, division and exponentiation operation. (5)
# Program make a simple calculator that can add, subtract, multiply and divide using functions

# define functions
def add(x, y):
“””This function adds two numbers”””

return x + y

def subtract(x, y):
“””This function subtracts two numbers”””

return x – y

def multiply(x, y):
“””This function multiplies two numbers”””

return x * y

def divide(x, y):
“””This function divides two numbers”””

return x / y

# take input from the user
print(“Select operation.”)

choice = input(“Enter choice(1/2/3/4):”)

num1 = int(input(“Enter first number: “))
num2 = int(input(“Enter second number: “))

if choice == ‘1’:
print(num1,”+”,num2,”=”, add(num1,num2))

elif choice == ‘2’:
print(num1,”-“,num2,”=”, subtract(num1,num2))

elif choice == ‘3’:
print(num1,”*”,num2,”=”, multiply(num1,num2))

elif choice == ‘4’:
print(num1,”/”,num2,”=”, divide(num1,num2))
print(“Invalid input”)

22.a) What do you mean by mutability of a data structure ? Explain with the help examples , why we say that list are mutable while tuples are immutable. (3)
Python data structures are either mutable (changeable) or not. Strings are not mutable – once created they cannot be modified in situ (though it is easy to create new, modified versions). Lists are mutable, which means lists can be changed after being created; a particular element of a list may be modified. Either single elements or slices of lists can be modified by assignment:
>>> x
[1,4,9,’new end of list’] >>> x[2] = 16
>>> x
[1,4,16,’new end of list’] >>> x[2:3] = [9,16,25]
[1,4,9,16,25,’new end of list’]
Tuples are essentially immutable lists. There is a different notation used to construct tuples (parentheses instead of brackets), but otherwise the same operations apply to them as to lists as long as the operation does not change the tuple. (For example, sort, reverse and del cannot be used.)
x = (1,”string”)
x = ()   # empty tuple
x = (2,) # one element tuple requires a trailing comma (which is legal
# for any length tuple also) to distinguish them from expressions
b) Write a python program to count number of vowels,consonants,words and question marks in a given string.  (6)
a = “hello world”
>>> vowels = “aeiouy”
>>> Consonants = “bcdfghjklmnpqrstvexz”
>>> Quest_mark = “?”
>>> space = ” ”

>>> nv = 0
>>> nc = 0
>>> nq = 0
>>> nw = 1

>>>for char in a:
…     if char in vowels:
…         nv += 1
…     elif char in consonants:
…         nc += 1
…     elif char in Quest_mark:
…         nq += 1
…     elif char in space:
…         nw += 1

>>>print nv
>>>print nw
>>>print nc
>>>print nq
 c) Write a python program to input a list of n numbers. Calculate and display average of numbers. Also display the cube of each value in the list           (5)

count = 0
total = 0.0
cube = 0
while True:
line = input(‘Enter the number: ‘)
if line:
n = int(line)
count = count + 1
total = total + n
cube= n*n*n
print(‘cube:’, cube)

except ValueError as err:
print(‘Enter a numeric value.’)
print(‘cube:’, cube)
if count:
print(‘average:’, total/count)


num_array = list ()

num = raw_input(“Enter how many elements you want:”)

avg = 0
total = 0

print’Enter numbers in array: ‘

for i in range(int (num)):

n = raw_input(“num :”)

num_array.append (int(n))
cube = num_array[i] * num_array[i]* num_array[i]

print cube
total = num_array[i] +total

avg = total / n
print avg
23.a) Write a python program to create a dictionary of roll numbers and names of 5 students. Display the contents of dictionary in alphabetical order of names. (7)

Create and initialize a dictionary:
>>> roll = {‘max’:1023, ‘sue’:404, ’abc’:1034:,’sdf’: 1234,’jhkl’: 6789}

To get the list in sorted form:
>>> x = sorted (roll. Keys ())
>>>for item in x.items():
…     print(items)

b) Write a python program to create a text file and input a line of text to it . Display the line of text with all punctuation marks removed. (7)
file = open(“ifile”, “w”)
file.write(“hello world in the new file”)
# strips all punctuatuation
import string, os

def strip_punct(ifile):
exclude = set(string.punctuation)

f = open(‘newfile.txt’, ‘r’)
text = f.readlines()

op_file_path = str(ifile) + ‘.punct_stripped’
if os.path.isfile(op_file_path): # Checks if o/p file exists
os.remove(op_file_path) # deletes the existing o/p file

for x in xrange(0,len(text)):
s = text[x]
return op_file_path

if __name__ == “__main__”:
print “Input file path: ”
ifile = raw_input()

24.a) Define the terms class , attributes , method and instance with the help of an example   (4)

Class: A user-defined prototype for an object that defines a set of attributes that characterize any object of the class. The attributes are data members (class variables and instance variables) and methods, accessed via dot notation.
Instance: An individual object of a certain class. An object obj that belongs to a class Circle, for example, is an instance of the class Circle.
Method : A special kind of function that is defined in a class definition.
Class attributes are attributes which are owned by the class itself. They will be shared by all the instances of the class. Therefore they have the same value for every instance. We define class attributes outside of all the methods, usually they are placed at the top, right below the class header.

b) Create a class car with attributes model, year, and price and a method cost () for displaying price. Create two instances of the class and call the method for each instance. (5)
  1. # declare a class
  2. classCar:
  3. self.model = model
  4. self.year=year
  5. self.price=2500000
  6. def cost(self):
  7. Return self.price
  8. if __model__ ==’__main__’:
  9. c=Car()#
  10. Price= C.cost()
  11. print”Car Info: “
  12. print”model: %s”%c.model
  13. print”year %s”%year
  14. print”price” %d price
c) Write a python program to create a file containing 10 numbers . Read contents of the file and display the square of each number. (5)
dataFile = open(“temp1”, “w”)
for line in range(10):
sq= line * line
dataFile = open(“temp1”, “r”)
print (datafile)

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