# UnionFind 参考は以下のサイト
# https://note.nkmk.me/python-union-find/
from collections import defaultdict

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        group_members = defaultdict(list)
        for member in range(self.n):
            group_members[self.find(member)].append(member)
        return group_members

    def __str__(self):
        return '\n'.join(f'{r}: {m}' for r, m in self.all_group_members().items())




def is_ok(x):
    uf = UnionFind(N+1)
    for i,l in enumerate(L):
        for ll in l:
            if x<=ll:
                uf.union(i,i+ll)
    return uf.same(0,N)


def meguru_bisect(ng, ok):
    while (abs(ok - ng) > 1):
        mid = (ok + ng) // 2
        if is_ok(mid):
            ok = mid
        else:
            ng = mid
    return ok


# 非クラス版
base = 37; mod = 10**9 + 9
pw = None
def rolling_hash(s):
    l = len(s)
    h = [0]*(l + 1)
    v = 0
    for i in range(l):
        h[i+1] = v = (v * base + ord(s[i])) % mod
    return h
# RH前に、必要な長さの最大値分のpow-tableを計算しておく
def setup_pw(l):
    global pw
    pw = [1]*(l + 1)
    v = 1
    for i in range(l):
        pw[i+1] = v = v * base % mod
def get(h, l, r):
    return (h[r] - h[l] * pw[r-l]) % mod



S = list(input())
N = len(S)
SR = S[::-1]
setup_pw(N+5)
ST = rolling_hash(S)
SRT = rolling_hash(SR)
L = [[] for _ in range(N)]
for i in range(N):
    for j in range(1,N-i+1):
        if get(ST,i,i+j)==get(SRT,N-i-j,N-i):
            L[i].append(j)

print(meguru_bisect(N+1,1))