S = input()
N = len(S)
T = S[::-1]
E = [[] for _ in range(N)]
l = 0
for r in range(1, N + 1):
    r2 = r;
    l2 = l
    while r2 - l2 > 0:
        if S[l2:r2] == T[N - r2:N - l2]:
            while r2 - l2 > 0:
                E[l2].append(r2)
                l2 += 1;
                r2 -= 1
        l2 += 1;
        r2 -= 1

r = N
for l in range(1, N):
    r2 = r;
    l2 = l
    while r2 - l2 > 0:
        if S[l2:r2] == T[N - r2:N - l2]:
            while r2 - l2 > 0:
                E[l2].append(r2)
                l2 += 1;
                r2 -= 1
        l2 += 1;
        r2 -= 1

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])