S = input()

n = len(S)
ans = 1
for i in range(n):
    j = 0
    res = 1
    while i - j - 1 >= 0 and i + j + 1 < n:
        j += 1
        if S[i - j] == S[i + j]:
            res += 2
    ans = max(ans, res)
print(ans)