S = input()
N = len(S)
T = S[::-1]
E = [[i+1] for i in range(N)]
for i in range(N):
    for j in range(2, N - i + 1):
        if S[i:i + j] == T[N - i - j:N - i]:
            E[i].append(i + j)
dp = [0] * (N + 1)
dp[0] = N
for i in range(N):
    for j in E[i]:
        dp[j] = max(dp[j], min(dp[i], j - i))
print(dp[N])