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):
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(0, A - 2 * B))

Solution (Python):
import sys, math
input = sys.stdin.readline
rs = lambda: input().strip()
ri = lambda: int(input())
rl = lambda: list(map(int, input().split()))
mod = 10**9 + 7

A, B = rl()

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

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

Solution (Python):
import sys
def ISI(): return map(int, sys.stdin.readline().rstrip().split())
a, b = ISI()
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())
print(a-b*2 if a>=b*2 else '0')

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

Solution (Python):


import sys
import math
import time

import collections
from collections import deque
from collections import Counter
import queue
import copy
import bisect
import heapq
import itertools



sys.setrecursionlimit(10**7)






A, B = map(int,input().split())
ans = 0

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

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

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

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

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 2*B >= A else 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(0,a-2*b))

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

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

Solution (Python):
import itertools
import math
import fractions
import functools
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(0 if a-b*2 < 0 else a-b*2)

Solution (Python):

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

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

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

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

Solution (Python):
a, b = list(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):

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

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

a = x[0]
b = x[1]

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

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

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

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

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

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())
print(max(0, 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())
ans = a - b - b
if ans < 0:
    print('0')
else:
    print(ans)

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

Solution (Python):
import sys
import math
import bisect


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

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 <= 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):
n, m = map(int, input().split())
if 2*m>=n:
  print(0)
else:
  print(n-2*m)

Solution (Python):
import bisect,collections,copy,heapq,itertools,math,string
import sys
def S(): return sys.stdin.readline().rstrip()
def M(): return map(int,sys.stdin.readline().rstrip().split())
def I(): return int(sys.stdin.readline().rstrip())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())
A, B = M()
if A < 2*B:
    print(0)
else:
    print(A-2*B)

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

Solution (Python):
import fileinput

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

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

Solution (Python):
from sys import stdin

def main():
    A, B = [int(x) for x in stdin.readline().rstrip().split()]
    if A > 2*B:
        print(A - 2*B)
    else:
        print(0)
main()

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

Solution (Python):
from sys import stdin

A, B = [int(x) for x in stdin.readline().rstrip().split()]

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

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

Solution (Python):
def ABC_143_A():
    A,B = map(int, input().split())
    if A - 2*B >= 0:
        print(A-2*B)
    else:
        print(0)


if __name__ == '__main__':

    ABC_143_A()

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(0 if A-(B*2)<1 else 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())

a = A - B * 2

if a <= 0:
    print("0")
else:
    print(a)

Solution (Python):
import sys

def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

A,B = LI()

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

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

Solution (Python):

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

if __name__ == '__main__':
    main()

Solution (Python):
from collections import defaultdict, deque, Counter
from heapq import heappush, heappop
from itertools import permutations, accumulate, combinations, combinations_with_replacement
from math import sqrt, ceil, floor, factorial
from bisect import bisect_left, bisect_right
from copy import deepcopy
from operator import itemgetter
from functools import reduce


import sys
def I(): return int(input())
def Is(): return map(int, input().split())
def LI(): return list(map(int, input().split()))
def TI(): return tuple(map(int, input().split()))
def IR(n): return [I() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def TIR(n): return [TI() for _ in range(n)]
def S(): return input()
def Ss(): return input().split()
def LS(): return list(input())
def SR(n): return [S() for _ in range(n)]
def SsR(n): return [Ss() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
sys.setrecursionlimit(10**6)
MOD = 10**9+7
INF = float('inf')


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

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-2*B))

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

Solution (Python):
import sys
sys.setrecursionlimit(10 ** 6)

int1 = lambda x: int(x) - 1
def II(): return int(input())

def MI(): return map(int, input().split())
def MI1(): return map(int1, input().split())

def LI(): return list(map(int, input().split()))
def LI1(): return list(map(int1, input().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def printlist(lst, k='\n'): return k.join(list(map(str, lst)))
INF = float('inf')

def solve():
    a, b = MI()

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


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-b*2,0))

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

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

Solution (Python):
A, B = list(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(0, a-(b*2)))

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

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(A - 2 * B, 0))

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())

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

Solution (Python):
import sys
sys.setrecursionlimit(10 ** 5 + 10)
def input(): return sys.stdin.readline().strip()

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

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(0);exit()
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):
from collections import deque
from heapq import heapify,heappop,heappush,heappushpop
from copy import copy,deepcopy
from itertools import product,permutations,combinations,combinations_with_replacement
from collections import defaultdict,Counter
from bisect import bisect_left,bisect_right


from functools import reduce
from pprint import pprint

INF = float("inf")

def myinput():
    return map(int,input().split())

def mylistinput(n):
    return [ list(myinput()) for _ in range(n) ]

def mycol(data,col):
    return [ row[col] for row in data ]

def mysort(data,col,reverse_flag):
    data.sort(key=lambda x:x[col],reverse=reverse_flag)
    return data

def mymax(data):
    M = -1*float("inf")
    for i in range(len(data)):
        m = max(data[i])
        M = max(M,m)
    return M

def mymin(data):
    m = float("inf")
    for i in range(len(data)):
        M = min(data[i])
        m = min(m,M)
    return m

def mycount(ls,x):
    
    l = bisect_left(ls,x)
    r = bisect_right(ls,x)
    return (r-l)

def myoutput(ls,space=True):
    if space:
        if len(ls)==0:
            print(" ")
        elif type(ls[0])==str:
            print(" ".join(ls))
        elif type(ls[0])==int:
            print(" ".join(map(str,ls)))
        else:
            print("Output Error")
    else:
        if len(ls)==0:
            print("")
        elif type(ls[0])==str:
            print("".join(ls))
        elif type(ls[0])==int:
            print("".join(map(str,ls)))
        else:
            print("Output Error")

a,b = myinput()

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

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

Solution (Python):
from statistics import median


from fractions import gcd
from itertools import combinations 
from collections import deque
from collections import defaultdict
import bisect










import sys
sys.setrecursionlimit(10000000)
mod = 10**9 + 7

def readInts():
  return list(map(int,input().split()))
def main():
    a,b = readInts()
    print(a - b*2 if a - b*2 >= 0 else 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())
print(max(A-2*B,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())
print(max(a-2*b,0))

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

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

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())

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

Solution (Python):
from sys import stdin
def main():
    
    readline=stdin.readline
    A,B=map(int,readline().split())

    C=max(0,A-B*2)
    print(C)
if __name__=="__main__":
    main()

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

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

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

a, b = [int(x) for x in 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())
print(max(0,A-B-B))

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

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


if __name__ == '__main__':
    main()

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

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

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

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(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())

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())
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())
print(A-2*B) if 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())

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

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

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

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

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

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

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

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

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

Solution (Python):
a,b=[int(_) for _ in 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):
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())
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):
if __name__ == '__main__':
    a, b = map(int, input().split())
    print(max(0, 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 = map(int, input().split())
ans = a - (b * 2)
if ans >= 0:
    print(ans)
else:
    print(0)

Solution (Python):


def main():
    A, B = map(int, open(0).read().split())
    if (A >= B * 2):
        print(A - 2 * B)
    else:
        print(0)


main()

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

print(a-b*2 if a-b*2 > 0 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 = (int(x) for x in input().split())
b *= 2
p = a - b
if p < 0:
    print(0)
else:
    print(abs(p))

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

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

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

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

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

Solution (Python):
A, B = (int(x) for x in 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())
ans = max(0, a - 2 * b)
print(ans)

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

Solution (Python):






import sys
input = sys.stdin.readline

import math
from collections import deque
from fractions import gcd
from functools import lru_cache






MOD = 10**9+7
INF = float('inf')






def inputI(): return int(input().strip())
def inputS(): return input().strip()
def inputIL(): return list(map(int,input().split()))
def inputSL(): return list(map(str,input().split()))
def inputILs(n): return list(int(input()) for _ in range(n))
def inputSLs(n): return list(input().strip() for _ in range(n))
def inputILL(n): return [list(map(int, input().split())) for _ in range(n)]
def inputSLL(n): return [list(map(str, input().split())) for _ in range(n)]


def inv(n): return pow(n, MOD-2, MOD)


kaijo_memo = []
def kaijo(n):
  if(len(kaijo_memo) > n):
    return kaijo_memo[n]
  if(len(kaijo_memo) == 0):
    kaijo_memo.append(1)
  while(len(kaijo_memo) <= n):
    kaijo_memo.append(kaijo_memo[-1] * len(kaijo_memo) % MOD)
  return kaijo_memo[n]

gyaku_kaijo_memo = []
def gyaku_kaijo(n):
  if(len(gyaku_kaijo_memo) > n):
    return gyaku_kaijo_memo[n]
  if(len(gyaku_kaijo_memo) == 0):
    gyaku_kaijo_memo.append(1)
  while(len(gyaku_kaijo_memo) <= n):
    gyaku_kaijo_memo.append(gyaku_kaijo_memo[-1] * pow(len(gyaku_kaijo_memo),MOD-2,MOD) % MOD)
  return gyaku_kaijo_memo[n]

def nCr(n,r):
  if(n == r):
    return 1
  if(n < r or r < 0):
    return 0
  ret = 1
  ret = ret * kaijo(n) % MOD
  ret = ret * gyaku_kaijo(r) % MOD
  ret = ret * gyaku_kaijo(n-r) % MOD
  return ret


def factorization(n):
    arr = []
    temp = n
    for i in range(2, int(-(-n**0.5//1))+1):
        if temp%i==0:
            cnt=0
            while temp%i==0:
                cnt+=1
                temp //= i
            arr.append([i, cnt])
    if temp!=1:
        arr.append([temp, 1])

    if arr==[]:
        arr.append([n, 1])
    return arr


def lcm(a, b):
    return a * b // gcd (a, b)





A,B = inputIL()

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)=input().split()
(A,B)=(int(A),int(B))
Ans=A-(2*B)
if Ans<=0:
  Ans=0
print(Ans)

Solution (Python):
import os

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


if __name__ == "__main__":
	main()

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

if a > b * 2:
	print(a - b * 2)
elif a <= b * 2:
	print(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(A - 2 * B if A - 2 * B >= 0 else 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-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())

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())
print(0 if a<=2*b 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())
print(max(0, A-B*2))

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

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

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

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

ans = 0

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

Solution (Python):
import sys
import os
import math
import string

ii = lambda: int(sys.stdin.buffer.readline().rstrip())
il = lambda: list(map(int, sys.stdin.buffer.readline().split()))
fl = lambda: list(map(float, sys.stdin.buffer.readline().split()))
iln = lambda n: [int(sys.stdin.buffer.readline().rstrip()) for _ in range(n)]

iss = lambda: sys.stdin.buffer.readline().decode().rstrip()
sl = lambda: list(map(str, sys.stdin.buffer.readline().decode().split()))
isn = lambda n: [sys.stdin.buffer.readline().decode().rstrip() for _ in range(n)]

lcm = lambda x, y: x * y / math.gcd(x, y)

MOD = 10 ** 9 + 7
MAX = float('inf')


def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

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


if __name__ == '__main__':
    main()

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

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

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

Solution (Python):
w,c = map(int,input().split())
         
res = w - (2*c)

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

Solution (Python):
print(max(0,eval(input().replace(' ','-2*'))))

Solution (Python):
n=eval(input().replace(' ','-2*'));print(n if n>0 else 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())
if 2 * b >= a:
    print(0)
else:
    print(a - 2 * b)

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

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

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

Solution (Python):

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

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

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

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

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

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

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

Solution (Python):
a, b = map(int, input().split())
print(a-b*2 if a-b*2 > 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())
if 2*b >= a:
  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):
def main():
    import sys
    input = sys.stdin.readline
    sys.setrecursionlimit(10**7)
    from collections import Counter, deque
    
    from itertools import combinations, permutations, accumulate, groupby, product
    from bisect import bisect_left,bisect_right
    from heapq import heapify, heappop, heappush
    from math import floor, ceil
    

    
    

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

if __name__ == '__main__':
    main()

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(0,a-2*b))

Solution (Python):
A, B = (int(x) for x in input().split())

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

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

m=a-2*b

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

Solution (Python):
a, b = map(int, input().split())
tmp = (a - b*2)
if tmp >= 0:
  print(tmp)
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())
if A<B*2:
    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 = [int(x) for x in input().split()]
temp = a - 2 * b
ans = temp if temp > 0 else 0
print(ans)

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

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

Solution (Python):
import sys
from bisect import bisect_right as bsr
from collections import Counter as cnt
from collections import defaultdict as dd
from collections import deque
from fractions import gcd
from itertools import permutations as perm
from math import ceil, factorial, floor
from operator import itemgetter as ig

sys.setrecursionlimit(1000000)


args = None
INF = float("inf")
MOD = int(1e9 + 7)


def input(*ps):
    if type(ps[0]) is list:
        return [input(*ps[0][:-1]) for _ in range(ps[0][-1])]
    elif len(ps) == 1:
        return ps[0](next(args))
    else:
        return [p(next(args)) for p in ps]


def yesno(v, yes="Yes", no="No", upper=False):
    if upper:
        print([yes.upper(), no.upper()][not v])
    else:
        print([yes, no][not v])


def main():
    """エントリーポイント"""
    A, B = input(int, int)
    ans = A - B - B
    print(ans if 0 < ans else 0)


if __name__ == '__main__':
    args = iter(sys.stdin.read().split())
    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())
if a < b * 2:
    print(0)
else:
    print(a-(b*2))

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

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

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

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