S = input()
N = len(S)
ans = 1
for i in range(1, N-1):
    a = min(i, N - i - 1)
    tmp = 1
    for j in range(1, a + 1):
        if S[i-j] == S[i+j]:
            tmp += 2
    ans = max(ans,tmp)
print(ans)