s = eval(input())

t = eval(input())

ans = 0

n = len(s)

for i in range(n):

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

    ans += 1



print(ans)
s = eval(input())

t = eval(input())



ans = 0

for i, j in zip(s, t):

    ans += i != j



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

s = eval(input())
t = eval(input())
ans = 0
for i, j in zip(s, t):
    ans += i != j
print(ans)

-n = len(s) -for i in range(n): -    if s[i] != t[i]: -        ans += 1 +for i, j in zip(s, t): +    ans += i != j