#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;

int main(){

    string S;
    cin >> S;
    assert(S.size() <= 5000);
    for (auto x : S) assert('a' <= x && x <= 'z');
    reverse(S.begin(), S.end());

    int N = S.size();
    vector<vector<bool>> ok(N+1, vector<bool>(N+1));

    for (int i=N; i>=1; i--){
        for (int j=i; j<=N; j++){
            ok[i][j] = (S[i-1] == S[j-1]);
            if (i+1 <= j-1) ok[i][j] = (ok[i][j] & ok[i+1][j-1]);
        }
    }

    vector<int> dp(N+1);
    dp[0] = 1e9;

    for (int i=1; i<=N; i++){
        for (int j=0; j<i; j++){
            if (ok[j+1][i]) dp[i] = max(dp[i], min(dp[j], i-j));
        }
    }

    cout << dp[N] << endl;

    return 0;
}