## https://yukicoder.me/problems/no/2204

B = 30
H = 9007199254740997

def main():
    S = input()
    # 後ろからの累積で対応
    hash_array = [0] * len(S)
    hs = 0
    for i in reversed(range(len(S))):
        hs *= B
        hs %= H
        hs += ord(S[i]) - ord("a") + 1
        hs %= H
        hash_array[i] = hs

    pow_b = [0] * (len(S) + 1)
    b = 1
    for i in range(len(S) + 1):
        pow_b[i] = b
        b *= B
        b %= H

    parindrome_map = [[i] for i in range(len(S))]
    for i in range(len(S)):
        hs = 0
        for j in range(i, len(S)):
            hs *= B 
            hs %= H
            hs += ord(S[j]) - ord("a") + 1
            hs %= H
            # 偶数長
            k = j - i
            j_ = j + 1
            i_ = j_ + k
            if i_ < len(S):
                if i_ == len(S) - 1:
                    h = hash_array[j_]
                else:
                    h = (hash_array[j_] - (hash_array[i_ + 1] * pow_b[k + 1]) % H) % H
                if hs == h:
                    parindrome_map[i_].append(i)
            
            # 奇数長
            k = j - i
            j_ = j + 2
            i_ = j_ + k
            if i_ < len(S):
                if i_ == len(S) - 1:
                    h = hash_array[j_]
                else:
                    h = (hash_array[j_] - (hash_array[i_ + 1] * pow_b[k + 1]) % H) % H
                if hs == h:
                    parindrome_map[i_].append(i)

    dp = [0 for _ in range(len(S))]
    for i in range(len(S)):
        for j in parindrome_map[i]:
            if j == 0:
                dp[i] = max(dp[i], i - j + 1)
            else:
                dp[i] = max(dp[i], min(dp[j], i - j + 1))
    print(dp[-1])




if __name__ == '__main__':
    main()