Problem:
 Score : 100 points    Problem Statement The window of Takahashi's room has a width of A . There are two curtains hung over the window, each of which has a horizontal length of B . (Vertically, the curtains are long enough to cover the whole window.)  We will close the window so as to minimize the total horizontal length of the uncovered part of the window.
Find the total horizontal length of the uncovered parts of the window then.      Constraints  1 \leq A \leq 100  1 \leq B \leq 100  A and B are integers.         Input Input is given from Standard Input in the following format:  A  B       Output Print the total horizontal length of the uncovered parts of the window.        Sample Input 1 12 4      Sample Output 1 4  We have a window with a horizontal length of 12 , and two curtains, each of length 4 , that cover both ends of the window, for example. The uncovered part has a horizontal length of 4 .       Sample Input 2 20 15      Sample Output 2 0  If the window is completely covered, print 0 .       Sample Input 3 20 30      Sample Output 3 0  Each curtain may be longer than the window.

Solution (Python):
arr = input().split()
a = int(arr[0])
b = int(arr[1])

if a - 2*b >= 0:
    print(a - 2*b)
else:
    print(0)

Solution (Python):
a, b =map(int, input().split())
print(max(0, a-2*b))

Solution (Python):
a, b = map(int, input().split())
n = a - 2 * b
if n > 0:
    print(n)
else:
    print(0)

Solution (Python):
A, B = list(map(int, input().split()))
print(max(0, A - 2 * B))

Solution (Python):
A, B = (int(x) for x in input().split())
A -= B * 2
if A < 0:
    print(0)
else:
    print(A)

Solution (Python):
a,b = map(int,input().split())

s = a - b * 2

if s < 0:
  s = 0
  
print(s)

Solution (Python):
A, B = map(int, input().split())

print(0 if B*2 > A else A-B*2)

Solution (Python):
A,B = map(int, input().split())

print(max(0, A-2*B))

Solution (Python):
a,b = map(int, input().split())
print(a - 2*b if 2*b < a else 0)

Solution (Python):
a, b = map(int, input().split())
print(max(a-b*2, 0))

Solution (Python):
a,b = map(int,input().split())
print(a-b*2 if a-b*2>=0 else 0)

Solution (Python):
def LI():
  return [int(s) for s in input().split()]
 
A,B = LI()
 
print(int(A-2*B)) if A > 2*B else print(0)

Solution (Python):
a, b = map(int, input().split())
if a - b * 2 > 0:
  print(a-b*2)
else:
  print(0)

Solution (Python):
A,B = map(int, input().split())
if A-2*B <= 0:
    print(0)
else:
    print(A-2*B)

Solution (Python):
x,y=list(map(int,input().split()))
if y*2<x:
  print (x-(y*2))
else:
  print('0')

Solution (Python):
A, B = map(int, input().split())

if A <= 2*B:
    print(0)

else:
    print(A - 2*B)

Solution (Python):
import math
from functools import reduce
from collections import deque
import sys
sys.setrecursionlimit(10**7)

def s(generator, splitter, mapper):
    return [ mapper(s) for s in generator().split(splitter) ]


def get_nums_l():
    return [ int(s) for s in input().split(" ")]


def get_nums_n(n):
    return [ int(input()) for _ in range(n)]

a,b = get_nums_l()
print(max(0, a - 2*b))

Solution (Python):
import sys

INPUT = lambda: sys.stdin.readline().rstrip()
MAP = lambda: map(int, INPUT().split())

sys.setrecursionlimit(10 ** 9)


def main():
    A, B = MAP()
    print(max(0, A - 2*B))


if __name__ == '__main__':
    main()

Solution (Python):
import sys
 
def main():
    A, B = map(int, input().split())
 
    if(A<=2*B):
        print('0')
 
    else:
        print(A-2*B)
 
main()

Solution (Python):
def main():
    a, b = map(int, input().split())
    diff = a - b*2
    if diff <= 0:
        print(0)
    else:
        print(diff)


if __name__ == "__main__":
    main()

Solution (Python):
a,b=map(int,input().split())
if a<=(2*b):
    print(0)
else:
    print(a-2*b)

Solution (Python):
a, b = map( int, input().split())
print( max( 0, a - b * 2 ))

Solution (Python):
A, B = map(int, input().split())
print(max(A-B*2,0))

Solution (Python):
A,B = map(int,input().split())

ans = A-B*2
if ans>0:
    print(ans)
else:
    print(0)

Solution (Python):
def main():
    a, b = map(int, input().split())

    if a - b -b > 0:
        print(a-b-b)
        exit()

    print(0)

if __name__ == '__main__':
    main()

Solution (Python):
a,b = map(int, input().split())

print(max(a-2*b, 0))

Solution (Python):
n,m  = map(int, input().split())

if 2 * m <= n:
  print(n - 2 * m)
else:
  print(0)

Solution (Python):
A,B=input().split()
A=int(A)
B=int(B)
if A-2*B>=0:
    print(A-2*B)
else:
    print(0)

Solution (Python):
a,b=map(int,input().split())
print(a-2*b if a>2*b else 0)

Solution (Python):
a,b=map(int,input().split())
if a-2*b>=0:
  print(a-2*b)
else:
  print(0)

Solution (Python):
import itertools

def main():
    A, B = map(int, input().split())
    print(max(0, A-(B*2)))
    return 0
if __name__ == '__main__':
    main()

Solution (Python):
A, B = map(int, input().split())

print(max(0, A - 2 * B))

Solution (Python):
a, b=map(int, input().split())
if a > 2*b:
    print(a-2*b)
else:
    print("0")

Solution (Python):
A,B=map(int,input().split())
if A > 2*B:
  print(A - 2*B)
else: print(0)

Solution (Python):
a = list(map(int, input().split()))
print(max(0, a[0]-2*a[1]))

Solution (Python):
a,b=map(int,input().split())
print(a-b*2 if a>b*2 else 0)

Solution (Python):
x,y = map(int,input().split())
if y*2 > x:
    print(0)
else:
    print(x-y*2)

Solution (Python):
a,b = map(int, input().split())
if a - (b*2) < 0:
  print('0')
else:
  print(a - (b*2))

Solution (Python):
a, b = map(int,input().split())

if a <= b*2 :
  print(0)
else:
  print(int(a-b*2))

Solution (Python):
ns = input().split(" ")
a = int(ns[0])
b = int(ns[1])
if (a - 2 * b) > 0:
  print(a - 2 * b)
else:
  print(0)

Solution (Python):
"""
author : halo2halo
date : 9, Jan, 2020
"""

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
sys.setrecursionlimit(10 ** 7)

A, B = map(int, readline().split())
S=A-2*B
print(S if S>0 else 0)

Solution (Python):
A,B =map(int,input().split())
print(A-B*2 if A>B*2 else 0)

Solution (Python):
a ,b = map(int, input().split(" "))

if (b*2) >= a:
	print(0)
else:
	print(a - (b*2))

Solution (Python):
a, b = map(int, input().split())

if b * 2 >= a:
    print(0)
else:
    print(a-b*2)

Solution (Python):
def main():
    a, b = map(int, input().split())
    print(max(0, a-b*2))

if __name__ == '__main__':
    main()

Solution (Python):
a, b = map(int, input().split())
ans = a-b*2

if ans < 0:
  print(0)
else:
  print(ans)

Solution (Python):
A, B = map(int, input().split(' '))

ans = A - 2*B

if ans < 0:
    print(0)
else:
    print(ans)

Solution (Python):
A, B = map(int, input().split())

if A <= B * 2:
    print(0)
else:
    print(A - B * 2)

Solution (Python):
a, b = map(int, input().split())

print(max(a - 2 * b, 0))

Solution (Python):
a,b=map(int,input().split())
print(a-b*2 if b*2 < a else 0)

Solution (Python):
a, b = map(int, input().split())
ans = max(0, a - b * 2)
print(ans)

Solution (Python):
a, b = map(int, input().split())

x = a - 2 * b
if (x <= 0):
   print(0)
else:
   print(x)

Solution (Python):
a,b = map(int, input().split())
print(max(0,a-2*b))

Solution (Python):
A, B = list(map(int, input().split()))

B2 = B*2

if A>B2:
  print(A-B2)
else:
  print(0)

Solution (Python):
A, B = [int(i) for i in input().split()]
if 2 * B > A:
    print(0)
else:
    print(A - 2 * B)

Solution (Python):
A,B = map(int,input().split())
K = A-2*B
if(A <= 2*B):
    print(0)
if(A > 2*B):
    print(K)

Solution (Python):
import sys
input = sys.stdin.buffer.readline

def main():
    A,B = map(int,input().split())
    if A >= 2*B:
        print(A-2*B)
    else:
        print(0)
        
if __name__ == "__main__":
    main()

Solution (Python):



A, B = map(int, input().split())

if A > 2*B : 
    print(A - 2*B)
else : 
    print(0)

Solution (Python):
a, b= map(int, input().split())

if a > b * 2:
    print(a-b*2)
else:
    print(0)

Solution (Python):
a,b = map(int,input().split())

print(max(a-b*2,0))

Solution (Python):
INT = lambda: int(input())
INTM = lambda: map(int,input().split())
STRM = lambda: map(str,input().split())
STR = lambda: str(input())
LIST = lambda: list(map(int,input().split()))
LISTS = lambda: list(map(str,input().split()))
def do():
    a,b=INTM()
    print(max(0,a-2*b))
if __name__ == '__main__':
    do()

Solution (Python):
a, b = map(int, input().split())
print(max(a-2*b, 0))

Solution (Python):

a, b = map(int,input().split())

c=a-2*b

if c >= 0:
    print(a-2*b)
else:
    print(0)

Solution (Python):
a,b = map(int,input().split())
ans = a - b*2
if ans < 0:
  ans = 0
print(ans)

Solution (Python):
a,b=map(int,input().split())
print(max((a-b*2),0))

Solution (Python):
A, B = list(map(int, input().split())) 
if 2*B >= A:
  print(0)
else:
  print(A-(2*B))

Solution (Python):
A, B = map(int, input().split())
if(2*B >= A):
  print("0")
else:
  print(A-2*B)

Solution (Python):
a, b = map(int, input().split())
print(max(0, a-2*b))

Solution (Python):
A, B = map(int, input().split())
if A < 2*B:
  print(0)
else:
  print(A-2*B)

Solution (Python):
A, B = [int(i) for i in input().split()]
if A <= B * 2:
    print('0')
else:
    print(A - B * 2)

Solution (Python):
from sys import stdin
import sys

def ria(sep = ''):
    if sep == '' :
        return list(map(int, input().split())) 
    else: return list(map(int, input().split(sep)))
def rsa(sep = ''):
    if sep == '' :
        return input().split() 
    else: return input().split(sep)
def ri(): return int(input())
def rd(): return float(input())
def rs(): return input()

def main():
    A, B = map(int, input().split())
    print (max(0, A - 2 * B))


if __name__ == "__main__":
    main()

Solution (Python):
A, B = map(int, input().split())

print(max(A - B * 2, 0))

Solution (Python):
a,b = list(map(int,input().split()))
c = 0 if a <= b * 2 else a - b*2
print(c)

Solution (Python):
def main():
    A, B = map(int, input().split(" "))
    print(max(0, A - 2 * B))


if __name__ == '__main__':
    main()

Solution (Python):
a,b=map(int,input().split())
print(max(0,a-2*b))

Solution (Python):

A,B = map(int,input().split())

ans = A - 2 * B
if ans < 0:
    print(0)
else:
    print(ans)

Solution (Python):
a, b = map(int, input().split())

if a <= b * 2:
    print(0)
else:
    ans = a - b * 2
    print(ans)

Solution (Python):
A,B = map(int, input().split())
print(A-2*B if (A-2*B) > 0 else 0)

Solution (Python):
A, B = map(int, input().split())
print(max(A - 2 * B, 0))

Solution (Python):
a, b = [int(i) for i in input().split()]
x = a-b*2
print(x if x>0 else 0)

Solution (Python):
a, b = map(int, input().split())

print(max(0, a - 2 * b))

Solution (Python):
A,B = map(int,input().split())
ans = A-2*B
if(ans < 0):
	ans = 0
print(ans)

Solution (Python):

a,b = map(int,input().split())
if a >= b*2:
 print(a-b*2)
else:
 print(0)

Solution (Python):
a,b = map(int,input().split())
if a>=2*b:
    print(a-2*b)
else:
    print(0)

Solution (Python):
a,b=map(int,input().split())
if a<b*2:
    print(0)
else:
    print(a-b*2)

Solution (Python):

A, B = map(int, input().split())

if A - B * 2 < 0:
    print(0)
else:
    print(A - B * 2)

Solution (Python):
A, B = map(int, input().split())
if(A-2*B >= 0):
        print(A-2*B)
else:
        print(0)

Solution (Python):
a, b = [int(i) for i in input().split()]

if a <= b * 2:
  print(0)
else:
  print(a - b * 2)

Solution (Python):
a,b = map(int, input().split())
if a > b*2:
    print(a-b*2)
else:
    print("0")

Solution (Python):
def main():
	
	n,k = map(int,input().split())
	
	
	
	
	

	if n - 2*k < 0:
		print(0)
	else:
		print(n - 2*k)

 
if __name__ == '__main__':
	main()

Solution (Python):
a, b = map(int, input().split())
print(max(0, a - b * 2))

Solution (Python):
A, B = map(int,input().split())

ans = A - 2*B

if ans < 0:
    ans = 0

print(ans)

Solution (Python):
A, B = map(int, input().split())
print(max(A - 2 * B, 0))

Solution (Python):
A, B = map(int, input().split())
if A>=B*2:
  print(A-(B*2))
else:
  print(0)

Solution (Python):
a, b=map(int, input().split())
kari=a-b-b
if kari>0:
  kotae=kari
else:
  kotae=0
print(kotae)

Solution (Python):
a,b = map(int,input().split())
c = a-2*b
if c<0:
    print(0)
else:
    print(c)

Solution (Python):
a, b = map(int, input().split())
print(max(a - 2*b, 0))

Solution (Python):
a,b=map(int,input().split())
print(a-2*b if a>=2*b else 0)

Solution (Python):
a, b = map(int,input().split())
if a <= 2*b:
    print(0)
else:
    print(a-2*b)

Solution (Python):
A,B=map(int, input().split())
if A < 2*B:
  print(0)
else:
  print(A-2*B)

Solution (Python):
a,b = map(int,input().split())
if a-2*b > 0:
    print(a-2*b)
else:
    print(0)

Solution (Python):
a, b = map(int, input().split())

c = a - (b * 2)
print(c if c >= 0 else 0)

Solution (Python):
A,B=map(int,input().split())

if A-2*B>=0:
  print(A-2*B)
else:
  print(0)

Solution (Python):
A,B=map(int,input().split())
print(max(A-2*B,0))

Solution (Python):
A,B=map(int,input().split())
if A-2*B<=0:
    print(0)
else:
    print(A-2*B)

Solution (Python):
A, B = map(int, input().split())

ans = max(0, A - 2*B)
print(ans)

Solution (Python):
A,B = list(map(int, input().split()))
l = A-B*2

if l < 0:
    print(0)
else:
    print(l)

Solution (Python):
a,b=map(int,input().split())
if a>2*b:
    print(a-2*b)
else:
    print(0)

Solution (Python):

 
import math
import itertools
import sys
import copy
 

A, B = map(int, input().split())



if A <= B*2 :
  print (0)
else :
  print (A - B*2)

Solution (Python):
a,b = map(int,input().split())
print(max(a-2*b,0))

Solution (Python):
a,b=map(int,input().split())
print(a-b*2 if a-b*2>0 else 0)

Solution (Python):
A, B = list(map(int, input().split()))
print(0 if A <= 2 * B else A - 2 * B)

Solution (Python):
data = input().split(' ')
data_int = [int(data[i]) for i in range(2)]

result = data_int[0] - 2 * data_int[1]

if(result < 0):
    print(0)
else:
    print(result)

Solution (Python):
a,b = map(int, input().split())
l = a - b*2
print(0) if l < 0 else print(l)

Solution (Python):
A,B  = map(int,input().split())

ans = 0
if A>2*B:
    ans = A-2*B

print(ans)

Solution (Python):
a,b = map(int, input().split())
res = a - b - b
print(0 if res < 0 else res)

Solution (Python):
A, B = map(int, input().split())

print(max(A - 2 * B, 0))

Solution (Python):
A,B = map(int,input().split())
if A-2*B<=0:
    print('0')
else:
    print(A-2*B)

Solution (Python):
A,B = map(int,input().split())
r=A-2*B
if r <=0:
  print(0)
else:
  print(r)

Solution (Python):
x = input()
x_list = x.split(" ")
a = int(x_list[0])
b = int(x_list[1])
if a >= 2*b:
    print(a - 2*b)
else:
    print(0)

Solution (Python):
a, b = map(int, input().strip().split())

n = a - b * 2

if n <= 0:
    print(0)
else:
    print(n)

Solution (Python):
a, b = map(int, input().split())
print ( max(0, a-2*b) )

Solution (Python):
a,b = map(int,input().split())
if 2*b >= a:
  print(0)
else:
  print(a-2*b)

Solution (Python):
A, B = map(int, input().split())
C = A-2*B
if C<0:
    print(0)
else:
    print(C)

Solution (Python):
A,B=(int(x) for x in input().split())
if A-B*2<=0:
  print(0)
else:
  print(A-B*2)

Solution (Python):
A, B = map(int, input().split())

answer = A - B * 2

if answer >= 0:
    print(answer)
else:
    print(0)

Solution (Python):
from collections import defaultdict, deque, Counter
from heapq import heappush, heappop, heapify
import math
import bisect
import random
from itertools import permutations, accumulate, combinations
import sys
import string
from bisect import bisect_left, bisect_right
from math import factorial, ceil, floor
from functools import reduce
import numpy as np

INF = float('inf')
def LI(): return list(map(int, sys.stdin.readline().split()))
def I(): return int(sys.stdin.readline())
def LS(): return sys.stdin.readline().split()
def S(): return sys.stdin.readline().strip()
def IR(n): return [I() for i in range(n)]
def LIR(n): return [LI() for i in range(n)]
def SR(n): return [S() for i in range(n)]
def LSR(n): return [LS() for i in range(n)]
def SRL(n): return [list(S()) for i in range(n)]
def MSRL(n): return [[int(j) for j in list(S())] for i in range(n)]
mod = 1000000007



input = sys.stdin.readline


A,B=LI()
if A<B:
    print(0)
    exit()
if A-B*2>=0:
    print(A-B*2)
elif A-B*2<0:
    print(0)

Solution (Python):

a, b = map(int, input().split())

c = a - b*2

if c<=0:
    print(0)
else:
    print(c)

Solution (Python):
A, B = map(int, input().split())
if (A-B*2)<0:
    print(0)
else:
    print(A-B*2)

Solution (Python):
A, B = map(int, input().split())
answer = max(0, A - 2*B)
print(answer)

Solution (Python):
a,b = map(int,input().split())
print(max(0,a-2*b))

Solution (Python):
a,b = map(int,input().split())
if a <= b*2:
  print(0)
else:
  print(a-b*2)

Solution (Python):
a, b = map(int, input().split())

if a < b*2:
    print(0)
else:
    print(a-b*2)

Solution (Python):
a, b = map(int, input().split())

print(max(0, a-2*b))

Solution (Python):
A, B = map(int,input().split())
total = A-2*B
if total <= 0:
    print("0")
else:
    print(total)

Solution (Python):
A,B = map(int, input().split())
if B*2 >= A:
  print('0')
else:
  print(A-B*2)

Solution (Python):
a, b = map(int, input().split())
print(max(0, a - b * 2))

Solution (Python):
a, b = map(int,input().split())
print(max(0, a - 2 * b))

Solution (Python):
A, B = map(int, input().split())
ans = A-B*2
if ans >= 0:
  print(ans)
else:
  print(0)

Solution (Python):
A,B=map(int,input().split())
if A>=(B*2):
   print(A-(B*2))
else:
   print(0)

Solution (Python):
a, b = [int(x) for x in input().split()]
print(max(a - b * 2, 0))

Solution (Python):
a, b = map(int, input().split())

if a < b * 2:
    print("0")
else:
    ans = a - b * 2
    print(ans)

Solution (Python):
A, B = map(int, input().split())
print(max(A-2*B, 0))

Solution (Python):
A,B = map(int,input().split())
if A - B*2 < 0:
  print(0)
else:
  print(A-B*2)

Solution (Python):
window,c=map(int,input().split())

if window<c*2:
  print(0)
else:
  print(window-c*2)

Solution (Python):
a,b=map(int,input().split())
print(max([0,a-2*b]))

Solution (Python):
a,b=map(int,input().split())
print(max(0,a-2*b))

Solution (Python):
a, b = list(map(int, input().split()))
if a > b*2:
    print(a-b*2)
else:
    print(0)

Solution (Python):
a, b = map(int, input().split())

print(max(0, a - 2 * b))

Solution (Python):
A,B=map(int,input().split())
if A-2*B<0:
  print(0)
else:
  print(A-2*B)

Solution (Python):
A,B=map(int,input().split())
if A<=2*B:
  print(0)
else :
  print(A-(2*B))

Solution (Python):
a,b=map(int,input().split())
if a<=b*2:
  print(0)
else:
  print(a-b*2)

Solution (Python):
a,b=map(int,input().split())
if a>b+b:
  print(a-b-b)
else:
  print(0)

Solution (Python):
a,b=map(int,input().split())
if a-2*b>=0:
  print(a-2*b)
else:
  print(0)

Solution (Python):
a,b=map(int,input().split())
if b*2<=a:
  print(a-b*2)
else:
  print(0)

Solution (Python):
a,b=map(int,input().split())

if a>=2*b:
  print(a-2*b)
  
else:
  print(0)

Solution (Python):
wide = [int(i) for i in input().split()]


if wide[0]-2*wide[1]>=0:
    print(wide[0]-2*wide[1])
    
else:
    print(0)

Solution (Python):
A,B = map(int,input().split())

ans = A - 2*B

if ans <=0:
    print(0)
else:
    print(ans)

Solution (Python):
a,b=map(int,input().split())
print(max(0,a-2*b))

Solution (Python):
import sys
a, b = map(int, sys.stdin.readline().split())

print(max(0, a - b * 2))

Solution (Python):
a,b=map(int,input().split())
ans=a-b*2

if ans<=0:
    print(0)
else:
    print(ans)

Solution (Python):
a,b=map(int,input().split())
c=a-2*b
if c>=0:
  print(c)
else:
  print(0)

Solution (Python):
def solve():
    A, B = map(int, input().split())
    if A <= B * 2:
        print(0)
    else:
        print(A - B * 2)


if __name__ == '__main__':
    solve()

Solution (Python):
A, B = map( int, input().split() )
print( max( A - 2 * B, 0 ) )

Solution (Python):
a,b=map(int,input().split())
print(max(a-2*b,0))

Solution (Python):
import sys
sys.setrecursionlimit(2147483647)
INF=float("inf")
MOD=10**9+7
input=lambda:sys.stdin.readline().rstrip()
def resolve():
    a,b=map(int,input().split())
    print(max(0,a-2*b))
resolve()

Solution (Python):
a,b=map(int,input().split())
print(max(0,a-b*2))

Solution (Python):
a, b = map(int, input().split())
if a < b*2:
    print(0)
else:
    print(a - b*2)

Solution (Python):
a, b = map(int, input().split())
ans = a - b*2

if ans >= 0:
  print(ans)
else:
  print(0)

Solution (Python):
A,B=map(int,input().split())
if (A<2*B):
    print(0)
else:
    print(A-2*B)

Solution (Python):
A,B=map(int,input().split())
print(max(0,A-2*B))

Solution (Python):
from sys import stdin

a,b = [int(x) for x in stdin.readline().rstrip().split()]

if a - 2*b >= 0:
    print(a - 2*b)
else:
    print(0)

Solution (Python):
a,b=map(int,input().split())
print(max(a-2*b,0))

Solution (Python):
a,b=map(int,input().split())
print(max(a-2*b,0))

Solution (Python):
A, B = map(int,input().split())
length_B = B * 2
if(A < length_B):
    ans = 0
else:
    ans = A - length_B
print(ans)

Solution (Python):
A,B=map(int, input().split())
ans = A - B*2 
if ans < 0:
    print(0)
else:
    print(ans)

Solution (Python):
import sys

a,b = (int(x) for x in input().split())

if a < 2*b :
    print(0)
else:
    print(a-2*b)

Solution (Python):
A,B=map(int,input().split())

C=A-2*B

if C>0:
	print(C)
else:
	print(0)

Solution (Python):
A, B = list(map(int, input().split()))
if B * 2 >= A :
	print(0)
else :
	print(A - B * 2)

Solution (Python):
A, B = map(int, input().split())
if A <= 2*B:
    print(0)
else:
    print(A - 2*B)

Solution (Python):
a , b = input().split()
A = int(a)
B = int(b)

if 2 * B >= A :
 print("0")
else:
 print(A - 2 * B)

Solution (Python):
A,B = list(map(int,input().split()))

if A - (B*2) <= 0:
    print(0)
else:
    print(A-(B*2))

Solution (Python):
a, b = map(int, input().split())
if a <= b * 2:
    print(0)
else:
    print(a - b * 2)

Solution (Python):
a, b = map(int, (input().split()))
print(max(a - 2 * b, 0))

Solution (Python):
import sys

line = sys.stdin.readline()
[a, b] = line.split(" ")
print(max(int(a) - int(b) * 2, 0))

Solution (Python):
a, b = list(map(int, input().split()))

d = a - 2*b

if d <= 0:
  print(0)
else:
  print(d)

Solution (Python):
a, b = map(int, input().split())
print(max(a - 2 * b, 0))

Solution (Python):
a, b = map(int ,input().split())
print(0 if a-2*b<0 else a-2*b)

Solution (Python):
a,b = map(int,input().split())
print(max(0,a-(2*b)))

Solution (Python):
a, b = map(int, input().split())

if a < b*2:
  print(0)
else:
  print(a-b*2)

Solution (Python):
A, B = map(int, input().split())

ans = max(0, A - 2*B)

print(ans)

Solution (Python):
a, b = map(int, input().split())

c = a - 2 * b

print(c if c > 0 else 0)

Solution (Python):
a,b=map(int,input().split())
print(max(0,a-2*b))

Solution (Python):
a,b=map(int,input().split())
if 2*b<=a:
    print("{}".format(a-2*b))
else:
    print("{}".format(0))

Solution (Python):
A, B = map(int, input().split())
if A - 2*B >= 0:
    print(A - 2*B)
else:
    print("0")

Solution (Python):
a,b = map(int,input().split())
print(a-2*b if 2*b<a else 0)

Solution (Python):
A, B = map(int, input().split())

print(max(0, A - B * 2))

Solution (Python):
A = list(map(int, input().split()))
ans = A[0]-A[1]*2
if ans < 0:
    print("0")
else:
    print(ans)

Solution (Python):
A, B = map(int, input().split())

ans = (max(A - B * 2, 0))

print(ans)

Solution (Python):
A, B = map(int, input().split())

ans = max(A - B * 2, 0)

print(ans)

Solution (Python):
A, B = map(int, input().split())

print(max(A - B * 2, 0))

Solution (Python):
a,b = map(int, input().split())
print(max(0, a-b-b))

Solution (Python):
A,B = map(int,input().split())

num = A - 2*B
if num >= 0:
	print(num)
else:
	print("0")

Solution (Python):
a, b = map(int, input().split())
print(max(0, a - 2 * b))

Solution (Python):
n,p=map(int,input().split())
if(n>2*p):
    print(n-2*p)
else:
    print(0)

Solution (Python):
a, b = map(int,input().split())
print(max(a-b*2, 0))

Solution (Python):
import sys

input = sys.stdin.readline
def INT(): return int(input())
def MAP(): return [int(s) for s in input().split()]

A, B = MAP()

C = A-2*B
print(C if C>0 else 0)

Solution (Python):
a,b = map(int,input().split())

print(max(a-2*b,0))

Solution (Python):
a,b=(int(x) for x in input().split())

ans=a-b-b
if ans<0:
	ans=0
print(ans)

Solution (Python):
A,B=list(map(int,input().split()))

if A<=2*B:
    output=0
else:
    output=A-2*B
print(output)

Solution (Python):
A,B = map(int,input().split())
if A>B*2:
  print(A-2*B)
else:
  print(0)

Solution (Python):
A,B=map(int,input().split())
print(A-2*B if A>2*B else 0)

Solution (Python):
a, b = map(int, input().split())
print(max(0,a-b*2))

Solution (Python):



A, B = map(int, input().split())

print(max(A - 2 * B, 0))

Solution (Python):
[print(length if length > 0 else 0) for length in [eval(input().replace(" ", "-") + "*2")]]

Solution (Python):
A, B = map(int, input().split())
if A-2*B > 0:
    print(A-2*B)
else:
    print('0')

Solution (Python):
A, B = map(int, input().split())

if A-2*B > 0:
    print(A-2*B)
else:
    print(0)

Solution (Python):
a,b = map(int,input().split())

if a >= 2*b:
  print(a-(2*b))
else:
  print("0")

Solution (Python):
a,b=input().split()
a=int(a)
b=int(b)
if a<=2*b:
  print('0')
else:
  print(a-2*b)

Solution (Python):
A, B = [int(x) for x in input().split()]
if A>2*B:
    print(A-2*B)
else:
    print(0)

Solution (Python):
l=list(map(int, input().split()))
A, B = l[0], l[1]
print(max(0, A-2*B))

Solution (Python):
A, B = map(int, input().split())
if A > 2 * B:
    print(A - 2 * B)
else:
    print(0)

Solution (Python):
import sys

num = list(map(int, input().split()))
if num[0]-2*num[1]>0:
  ans=num[0]-2*num[1]
else :
  ans= 0
print(ans)

Solution (Python):
a,b = map(int, input().split())

ans = a - b * 2

if (ans <= 0):
    print(0)
else:
    print(ans)

Solution (Python):


[A, B] = [int(i) for i in input().split()]

diff = A - B * 2
if diff < 0:
    print(0)
else:
    print(diff)

Solution (Python):
A,B = list(map(int, input().split()))

c = A - (B * 2)
if c >= 0:
    print(c)
else:
    print(0)

Solution (Python):
A,B = map(int, input().split())

if A-2*B>=0:
  print(A-2*B)
else:
  print("0")

Solution (Python):
a,b=map(int,input().split())
if a>b*2:
  print(a-b*2)
else:
  print(0)

Solution (Python):
import sys


def solve():
    readline = sys.stdin.buffer.readline
    mod = 10 ** 9 + 7
    a, b = list(map(int, readline().split()))
    print(max(0, a - b * 2))


if __name__ == '__main__':
    solve()

Solution (Python):
A,B=map(int,input().split())
C=B*2
if A>=C:
    print(A-C)
else:
    print(0)

Solution (Python):
import sys
input = sys.stdin.readline

def main():
    a, b = map(int, input().split())
    print(max(a - 2 * b, 0))

if __name__ == '__main__':
    main()

Solution (Python):
A, B = map(int,input().split())
result = A-(B*2)
if result < 0:
    print(0)
else:
    print(result)

Solution (Python):
import sys

if sys.platform =='ios':
    sys.stdin=open('input_file.txt')
    
a,b=map(int,input().split())

print(max(0,a-2*b))

Solution (Python):
A, B = map(int, input().split())

print(max(0, A - B * 2))

Solution (Python):
A, B = map(int, input().split())
ans = A - 2 * B
if ans < 0:
  ans = 0
print(ans)

Solution (Python):
a,b = map(int,input().split())

if a - b*2 >=0:
  print(a-b*2)
else:
  print(0)

Solution (Python):

import sys


def solve(A: int, B: int):
    ans = A - B*2
    if ans >= 0:
        print(ans)
    else:
        print(0)
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    A = int(next(tokens))  
    B = int(next(tokens))  
    solve(A, B)

if __name__ == '__main__':
    main()

Solution (Python):
A,B = map(int,input().split())

if B*2>A:
    print(0)
else:
    print(A-B*2)

Solution (Python):
a, b = map(int, input().split())
s = a - 2 * b
if s >= 0:
  print(s)
else:
  print("0")

Solution (Python):
a,b = map(int, input().split())

ans = a - b * 2 
if(ans < 0 ):
    ans = 0

print(ans)

Solution (Python):
a, b = map(int, input().split())

cover_b = b * 2
if cover_b > a:
  print(0)

else:
  print(a - cover_b)

Solution (Python):
A,B= map(int,input().split())



if A-(B*2) >=0:
    print(A-(B*2))
else:
    print(0)

Solution (Python):
a,b = map(int,input().split())
if a<b*2:
  print(0)
else:
	print(a-b*2)

Solution (Python):
a, b = map(int, input().split())

if a <= b * 2:
    print('0')
else:
    print(a - b * 2)

Solution (Python):

A, B = map(int, input().split())
print(max(0, A - (2*B)))

Solution (Python):
a,b = map(int,input().split())
print(a-2*b if a-2*b>=0 else 0)

Solution (Python):
a,b=map(int,input().split())
c=a-2*b
if c<=0:
    c=0
print(c)

Solution (Python):
A, B = map(int, input().split(' '))

x = A - B * 2
if x < 0:
    print(0)
else:
    print(x)

Solution (Python):
a,b=list(map(int,input().strip().split()))
if a<= b*2:
    print(0)
else:
    print(a-2*b)

Solution (Python):
a, b = map(int, input().split())
t = a - 2*b
if t <=0:
    print("0")
else:
    print(t)

Solution (Python):
A, B = map(int,input().split())
if A-2*B<=0:
    print(0)
else:
    print(A-2*B)

Solution (Python):
A, B = map(int, input().split())
if A - 2 * B >= 0:
    print(A - 2 * B)
else:
    print(0)

Solution (Python):
A, B = map(int, input().split())

if A - B * 2 > 0:
	print(A - B * 2)
else:
    print('0')

Solution (Python):

def main():
    K = [int(x) for x in input().split()]
    ans = K[0] - 2*K[1]
    print(max(ans, 0))


if __name__ == "__main__":
    main()

Solution (Python):
window_w, curtain_w = input().split()
window_w = int(window_w)
curtain_w = int(curtain_w)

remaining = window_w - curtain_w * 2

if(remaining < 0): remaining = 0

print(remaining)

Solution (Python):
A,B=map(int, input().split())
print(0 if A<B*2 else A-B*2)

Solution (Python):
A, B = map(int, input().split())
W = A - 2 * B
if W >= 0:
  print(W)
else:
  print(0)

Solution (Python):
a, b = map(int, input().split())

if a > b*2:
    print(a-b*2)
else:
    print(0)

Solution (Python):
while True:
    a,b = input().split()
    a = int(a)
    b = int(b)
    if 1<=a<=100 and 1<=b<=100:
        break
c = a-2*b
if c>0:
    print(c)
else:
    print(0)

Solution (Python):


a, b = map(int, input().split())
if (a - b * 2) > 0:
    print(a - b * 2)
else:
    print(0)

Solution (Python):
a, b = map(int,input().split())
if a - 2 * b <= 0:
    print(0)
else:
    print(a - 2 * b)

Solution (Python):
A, B = map(int, input().split())
print(max(0, A - 2 * B))

Solution (Python):
A, B = map(int, input().split())

ans = A - 2*B if 2*B < A else 0
print(ans)

Solution (Python):


A, B = map(int, input().split())

print(max(0, A-B*2))

Solution (Python):
a, b = map(int, input().split())

if 2 * b >= a:
    print('0')
else:
    print(a - 2 * b)

Solution (Python):
x = input().split()
a = int(x[0])
b = int(x[1])
c = max(0, a-2*b)
print(c)

Solution (Python):
A, B = (int(x) for x in input().split())
print(max(A-2*B,0))

Solution (Python):
a,b=map(int,input().split())
if 2*b>=a:
    print(0)
else:
    print(a-2*b)

Solution (Python):

A, B = map(int, input().split())
print(max(A - B * 2, 0))

Solution (Python):
print((lambda x:max(0, x[0]-2*x[1]))(list(map(int, input().split()))))