S = input()
length = len(S)
ans = 0

for i in range(length - 1):
    for j in range(i + 1, length + 1):
        l = list(S[i:j])
        l2 = l[::-1]
        if l == l2:
            if ans < len(l) and len(l) != length:
                ans = len(l)

print(ans)