#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second

const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll INF = 1LL << 60;
const ll MAX_N = 2e5;

struct ZAlgorithm{
    ZAlgorithm(){}

    vector<int> query(string S){
        int N = (int)S.size();
        vector<int> Z(N);
        Z[0] = N;
        int i=1, j=0;
        while(i < N){
            while(i+j<N && S[j]==S[i+j]) j++;
            Z[i] = j;

            if(j == 0){
                i++;
                continue;
            }

            int k=1;
            while(k < j && k+Z[k]<j){
                Z[i+k] = Z[k];
                k++;
            }
            i += k;
            j -= k;
        }

        return Z;
    }
};

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    string s;
    cin >> s;

    int n = (int)s.size();

    ZAlgorithm za;
    int lw = 1;
    int hi = n+1;
    int mid;
    while(hi-lw>1){
        mid = (lw+hi)/2;

        vector<bool> check(n+1, false);
        check[0]=true;
        for(int i=0; i<n; i++){
            if(!check[i]) continue;
            string t = "";
            for(int j=i; j<n; j++) t+=s[j];
            for(int j=n-1; j>=i; j--) t+=s[j];

            vector<int> z = za.query(t);
            for(int j=mid-1; j<n-i; j++){
                if(z[2*(n-i)-1-j]==j+1){
                    check[i+j+1] = true;
                }
            }
        }

        if(check[n]) lw = mid;
        else hi = mid;
    }

    cout << lw << endl;
}