S = eval(input())

T = eval(input())

count = 0

for i in range(len(S)):

    if S[i] != T[i]:

        count += 1

print(count)
S = eval(input())

T = eval(input())

print((sum(1 for s, t in zip(S, T) if s != t)))
S = eval(input())
T = eval(input())
count = 0
for i in range(len(S)):
    if S[i] != T[i]:
        count += 1
print(count)

S = eval(input())
T = eval(input())
print((sum(1 for s, t in zip(S, T) if s != t)))

-count = 0 -for i in range(len(S)): -    if S[i] != T[i]: -        count += 1 -print(count) +print((sum(1 for s, t in zip(S, T) if s != t)))