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):

from collections import defaultdict,deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys, random, itertools, math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt
def LI(): return list(map(int, input().split()))
def LF(): return list(map(float, input().split()))
def LI_(): return list(map(lambda x: int(x)-1, input().split()))
def II(): return int(input())
def IF(): return float(input())
def LS(): return list(map(list, input().split()))
def S(): return list(input().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def A():
    a, b = LI()
    print(max(0, a - 2 * b))
    return


def B():
    n = II()
    d = LI()
    ans = 0
    for i in range(n):
        for k in range(i+1, n):
            ans += d[i] * d[k]
    print(ans)
    return


def C():
    n = II()
    s = S()
    i = 0
    ans = 1
    for i in range(1, n):
        if s[i - 1] == s[i]:
            continue
        ans += 1
    print(ans)
    return


def D():
    n = II()
    l = LI()
    l.sort()
    ans = 0
    for i in range(n - 1, 0, -1):
        for k in range(i - 1, -1, -1):
            ab = l[i] - l[k]
            c = max(0, k - bisect_right(l, ab))
            ans += c
    print(ans)
    return


def E():
    n, m, l = LI()
    dist = [[inf] * n for i in range(n)]

    for _ in range(m):
        a, b, c = LI_()
        c += 1
        if c > l:
            continue
        dist[a][b] = c
        dist[b][a] = c

    supply = [[n] * n for i in range(n)]
    for k in range(n):
        distk = dist[k]
        for i in range(n):
            if i == k:
                continue
            disti = dist[i]
            distik = dist[i][k]
            for j in range(i + 1, n):
                if distik + distk[j] < disti[j]:
                    disti[j] = distik + distk[j]
                    dist[j][i] = disti[j]

    lis = [[] for i in range(n)]
    for i in range(n):
        for j in range(i + 1, n):
            if dist[i][j] <= l:
                supply[i][j] = 0
                supply[j][i] = 0
                lis[i].append(j)
                lis[j].append(i)

    for i in range(n):
        q = []
        for k in lis[i]:
            heappush(q, (0, k))
        supplyi = supply[i]

        while q:
            time, p = heappop(q)
            for k in lis[p]:
                if supplyi[k] > time + 1:
                    supplyi[k] = time + 1
                    heappush(q, (time + 1, k))

    q = II()
    for _ in range(q):
        s, t = LI_()
        if dist[s][t] == inf:
            print(-1)
            continue
        else:
            print(supply[s][t])
    return



def F():
    return


def G():
    return


def H():
    return


if __name__ == '__main__':
    A()

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())

if A>2*B:
    x=A-2*B
else:
    x=0

print(x)

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

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

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

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

Solution (Python):
import sys

stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline().rstrip()  

a, b = na()
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())
result = A-B*2 if A >= B*2 else 0
print(result)

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

x = a - 2 * b
if x < 0:
    ans = 0
else:
    ans = x

print(ans)

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

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

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

a=int(a)
b=int(b)

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

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

def main():
    A, B = map(int, input().split())

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

    else:
        print(A-2*B)

main()

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())
cartain = B*2

if A<=cartain :
    print(0)
else :
    print(A-cartain)

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

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

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

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

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

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

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

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

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

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

Solution (Python):
a = input().split() 
wn = int(a[0])
cn = int(a[1])

if (wn > cn*2):
    print (wn-cn*2)
else:
    print (0)

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

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


if __name__ == '__main__':
    main()

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

c = a - b * 2

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

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

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

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

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

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

print(ans)

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

Solution (Python):
n = input().split(' ')
A = int(n[0])
B = int(n[1])
C =2*B
if A > C:
    print(A-C)
else:
    print('0')

Solution (Python):
n = input().split(' ')
A = int(n[0])
B = int(n[1])
C =2*B
if A > C:
    print(A-C)
else:
    print('0')

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())

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

Solution (Python):



input_i = [int(i) for i in input().split()];



result  = input_i[0] - input_i[1]*2;

if(result>0):
    print(result);
else:
    print(0);

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

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

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

Solution (Python):
class Madowaku:
  def __init__(self, madowaku, curtain):
    self.madowaku = madowaku
    self.curtain = curtain
  
  def aki(self):
    ans = self.madowaku - self.curtain*2
    if ans >0:
      print(ans)
    else:
      print(0)
      
A, B = list(map(int, input().split(' ')))
solve = Madowaku(A,B)
solve.aki()

Solution (Python):
r = lambda : map(int, input().split(' '))

x,y = r()

ans = x - y - y
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 = input().split()
A = int(A)
B = int(B)

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

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

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

w_left = w - 2*c

if w_left <= 0:
    print('0')
else :
    print(w_left)

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

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

Solution (Python):
import sys
input = sys.stdin.readline
a, b = (int(i) for i in input().split())
ans = max(0, (a-2*b))
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 = [int(x) for x in input().split()]
ans = a - b*2
if ans < 0:
  ans = 0
print(ans)

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

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

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

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

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

Solution (Python):

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

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

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

Solution (Python):

from collections import defaultdict, Counter
from itertools import product, groupby, count, permutations, combinations
from math import pi, sqrt
from collections import deque
from bisect import bisect, bisect_left, bisect_right
from string import ascii_lowercase
from functools import lru_cache
import sys
sys.setrecursionlimit(10000)
INF = float("inf")
YES, Yes, yes, NO, No, no = "YES", "Yes", "yes", "NO", "No", "no"
dy4, dx4 = [0, 1, 0, -1], [1, 0, -1, 0]
dy8, dx8 = [0, -1, 0, 1, 1, -1, -1, 1], [1, 0, -1, 0, 1, 1, -1, -1]


def inside(y, x, H, W):
    return 0 <= y < H and 0 <= x < W


def ceil(a, b):
    return (a + b - 1) // b


def sum_of_arithmetic_progression(s, d, n):
    return n * (2 * s + (n - 1) * d) // 2


def gcd(a, b):
    if b == 0:
        return a
    return gcd(b, a % b)


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


def solve():
    return


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

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


B_2 = B*2

if A - B_2 >= 0:
    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())

remain_length = A - 2 * B

print(0) if remain_length < 0 else print(remain_length)

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

Solution (Python):
a,b = 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 - 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):
S = input()
li = S.split(" ")
a = int(li[0])
b = int(li[1])
if a<=b*2:
  print(0)
else:
  print(a-b*2)

Solution (Python):
def UnCoverWindow(a,b):
  sp = a - ( b * 2 )
  if sp<0:
    sp=0
  return sp

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

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

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

Solution (Python):
a,b = input().strip().split()
a = int(a)
b = int(b)
if b * 2 >= a:
  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 = map(int, input().split())

if a - 2 * b <= 0:
    print("{}".format(0))
else:
    print("{}".format(a - 2 * b))

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

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

Solution (Python):

import sys














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

if __name__ == "__main__":
    main()

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

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

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

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

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

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=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 - 2*B
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-b*2))

Solution (Python):
A,B = list(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(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):

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



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

Solution (Python):

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



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

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

Solution (Python):

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



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

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

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

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

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

c = 2*b

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

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

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

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

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

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

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

rest = a - b*2
if rest >-1:
    print(rest)
else:
    print(0)

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

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

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

Solution (Python):

"""
Created on Sat Nov 16 09:49:30 2019

@author: Shunya
"""

inputbox = input()
box = inputbox.split()
A = int(box[0])
B = int(box[1])
ans = A - B*2
if ans < 0:
    ans = 0
print (ans)

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())

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

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

Solution (Python):
input_lst = input().split(' ')
cand = int(input_lst[0]) -  2 * int(input_lst[1])
print(max(0, cand))

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

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

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

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

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

ans = num[0] - 2*num[1]
if ans < 0:
  print(0)
else:
  print(ans)

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

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

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

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

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


if __name__ == '__main__':
    main()

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

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

if a<=(b*2):
    print("0")
else:
    print("{}".format(a-b*2))

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

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

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

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

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

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

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

curtain_length = 2 * b

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

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

print(ans)

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

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

print(ans)

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


def main():
    sc = Scan()
    n = sc.intarr()
    a, b = n

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


class Scan():

    def intarr(self):
        line = input()
        array = line.split(' ')
        num_array = [int(n) for n in array]
        return num_array

    def strarr(self):
        line = input()
        array = line.split(' ')
        array[-1] = array[-1].strip('\n')
        return array


main()

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

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=(int(x) for x in input().split())

ret=a-b*2

if ret<0:
  print("0")
else:
  print(ret)

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

if __name__ == '__main__': main()

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

Solution (Python):
n=[int(x) for x in input().split()]
print(max(0,n[0]-n[1]*2))

Solution (Python):
n=[int(x) for x in input().split()]

ret=n[0] - n[1]*2
if ret<0:
    print(0)
else:
    print(ret)

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

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

Solution (Python):

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

Solution (Python):
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())
print(max(a-2*b, 0))

Solution (Python):


a,b = map(int,input().split())
l = a-2*b

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

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

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):
import numpy as np

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

c = a - 2 * b
print(int(np.max([c, 0])))

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

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

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

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

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

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

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

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

Solution (Python):
data=input().split()
a=int(data[0])-2*int(data[1])

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

Solution (Python):
x,y = map(int,input().split())
out = x - y*2
if out > 0:    
    print(out)
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:
    ans = a - 2*b
    print(ans)
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 = list(map(int, input().split()))
print(max(0, a-2*b))

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

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

A = int(A)

B = int(B)

if A>B*2:
  print (A-B*2)
  
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):
s = input().split()
A = int(s[0])
B = int(s[1])
l = A-2*B
if l < 0:
  l=0
print(l)

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

if a - 2*b<0:
    result = 0
else:
    result = a - 2*b

print(result)

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

Solution (Python):
s=list(map(int, input().split()))
A=s[0]
B=s[1]
if A<=2*B:
  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 = 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):
import sys
readline = sys.stdin.buffer.readline

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

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

Solution (Python):
A, B = 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 B * 2 >= A:
    print(0)
else:
    print(A - B * 2)

Solution (Python):
A, B = list(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(A - 2*B)
else :
    print(0)

Solution (Python):

import copy
import random
import bisect 
import fractions 
import math
import sys
import bisect

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

def LI(): return list(map(int, sys.stdin.readline().split()))

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

Solution (Python):
A, B = map(int, input().split())
diff = A - (2 * B)
if diff > 0:
  print(diff)
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 = (int(x) for x in 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(a - b*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):
s = list(map(int, input().split()))
A = s[0]
B = s[1]
if A >= B * 2:
    ans = A - B * 2
else:
    ans = 0
print(ans)

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

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