S = eval(input())

T = eval(input())

N = len(S)

cnt = 0

for i in range(N):

    cnt += (S[i] != T[i])



print(cnt)

S = eval(input())

T = eval(input())

cnt = 0

for i in range(len(S)):

    cnt += (S[i] != T[i])



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

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

-N = len(S) -for i in range(N): +for i in range(len(S)):