S = list(str(eval(input())))

T = list(str(eval(input())))



count = 0

for i in range(len(S)):

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

        count += 1

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

T = str(eval(input()))



count = 0

for i in range(len(S)):

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

        count +=1

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

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

-S = list(str(eval(input()))) -T = list(str(eval(input()))) +S = str(eval(input())) +T = str(eval(input()))