S = input()
len_S = len(S)
ans = 0
for i in range(len_S):
    t = 1
    for j in range(1, len_S):
        if i - j < 0 or i + j > len_S - 1:
            break
        if S[i-j] == S[i+j]:
            t += 2
    ans = max(ans, t)
print(ans)