S=eval(input())

T=eval(input())

count=0

for i in range(len(S)):

    count+=S[i]!=T[i]

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

T=eval(input())

print((sum(S[i]!=T[i] for i in range(len(S)))))
S = eval(input())
T = eval(input())
count = 0
for i in range(len(S)):
    count += S[i] != T[i]
print(count)

S = eval(input())
T = eval(input())
print((sum(S[i] != T[i] for i in range(len(S)))))

-count = 0 -for i in range(len(S)): -    count += S[i] != T[i] -print(count) +print((sum(S[i] != T[i] for i in range(len(S)))))