S = input()
N = len(S)

l = [[] for _ in range(N)]

for i in range(N):
    delta = 0
    while True:
        if i - delta >= 0 and i + delta < N:
            if S[i - delta] == S[i + delta]:
                l[i - delta].append(i + delta)
            else:
                break
        else:
            break
        delta += 1
    delta = 0
    while True:
        if i - delta >= 0 and i + 1 + delta < N:
            if S[i - delta] == S[i + delta + 1]:
                l[i - delta].append( i + 1 + delta)
            else:
                break
        else:
            break
        delta += 1
dp = [0] * (N + 1)
dp[0] = 10 ** 6
for i in range(N):
    m = dp[i]
    for j in l[i]:
        t = min(m,j - i + 1)
        dp[j + 1] = max(dp[j + 1],t)
print(dp[-1])