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

print((max(a-b,0)))
def main():

    x,t = list(map(int,input().split()))

    print((max(0,x-t)))



if __name__ == '__main__':

    main()

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

def main():
    x, t = list(map(int, input().split()))
    print((max(0, x - t)))


if __name__ == "__main__":
    main()

-a, b = list(map(int, input().split())) -print((max(a - b, 0))) +def main(): +    x, t = list(map(int, input().split())) +    print((max(0, x - t))) + + +if __name__ == "__main__": +    main()