S = eval(input())

T = eval(input())



cnt = 0



for i in range(len(S)):

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

    cnt += 1

print(cnt)

s = eval(input())

t = eval(input())

cnt = 0



for i in range(len(s)):

  if s[i] != t[i]:

    cnt += 1

print(cnt)

S = eval(input())
T = eval(input())
cnt = 0
for i in range(len(S)):
    if S[i] != T[i]:
        cnt += 1
print(cnt)

s = eval(input())
t = eval(input())
cnt = 0
for i in range(len(s)):
    if s[i] != t[i]:
        cnt += 1
print(cnt)

-S = eval(input()) -T = eval(input()) +s = eval(input()) +t = eval(input()) -for i in range(len(S)): -    if S[i] != T[i]: +for i in range(len(s)): +    if s[i] != t[i]: