S = list(eval(input()))



T = list(eval(input()))



def count_diff(a,b):



    cnt = 0

    for c1,c2 in zip(a, b):

        if c1 != c2:

            cnt += 1

    return cnt

    

print((count_diff(S, T)))
S = eval(input())



T = eval(input())



def count_diff(a,b):



    cnt = 0

    for c1,c2 in zip(a, b):

        if c1 != c2:

            cnt += 1

    return cnt

    

print((count_diff(S, T)))
S = list(eval(input()))
T = list(eval(input()))


def count_diff(a, b):
    cnt = 0
    for c1, c2 in zip(a, b):
        if c1 != c2:
            cnt += 1
    return cnt


print((count_diff(S, T)))

S = eval(input())
T = eval(input())


def count_diff(a, b):
    cnt = 0
    for c1, c2 in zip(a, b):
        if c1 != c2:
            cnt += 1
    return cnt


print((count_diff(S, T)))

-S = list(eval(input())) -T = list(eval(input())) +S = eval(input()) +T = eval(input())