S = input()
N = len(S)
T = S[::-1]
E = [[] for _ in range(N)]

def search(l, r):
    n2 = (r - l) // 2
    l0 = l + n2
    r0 = r - n2

    lb = 0
    ub = n2 + 1

    while ub - lb > 1:
        mid = (ub + lb) // 2
        if S[l0 - mid:r0 + mid] == T[N - r0 - mid:N - l0 + mid]:
            lb = mid
        else:
            ub = mid
    return lb

l = 0
for r in range(1, N + 1):
    x = (r - l) // 2 - search(l, r)
    l2 = l + x;
    r2 = r - x
    while r2 - l2 > 0:
        E[l2].append(r2)
        l2 += 1;
        r2 -= 1

r = N
for l in range(1, N):
    x = (r - l) // 2 - search(l, r)
    l2 = l + x;
    r2 = r - x
    while r2 - l2 > 0:
        E[l2].append(r2)
        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])