S=eval(input())

cnt = 0

for i in range(len(S)//2):

    if S[i] != S[len(S) - i - 1]:

        cnt += 1

print(cnt)
S=eval(input())

a=len(S)

print((sum(S[i]!=S[a-i-1]for i in range(a//2))))
S = eval(input())
cnt = 0
for i in range(len(S) // 2):
    if S[i] != S[len(S) - i - 1]:
        cnt += 1
print(cnt)

S = eval(input())
a = len(S)
print((sum(S[i] != S[a - i - 1] for i in range(a // 2))))

-cnt = 0 -for i in range(len(S) // 2): -    if S[i] != S[len(S) - i - 1]: -        cnt += 1 -print(cnt) +a = len(S) +print((sum(S[i] != S[a - i - 1] for i in range(a // 2))))