#include<bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
main(){
    string S;
    cin >> S;
    int N = S.size();
    int maxi = 0;
    rep(i,N){
        int cnt = 1;
        rep(j,N-1){
            int ind = j + 1;
            if(i - ind < 0 || i + ind >= N)break;
            if(S[i - ind] == S[i + ind])cnt += 2;
        }
        maxi = max(maxi, cnt);
    }
    rep(i,N-1){
        int cnt = 0;
        rep(j,N){
            int ind = j;
            if(i - ind < 0 || i + ind + 1 >= N)break;
            if(S[i - ind] == S[i + ind + 1])cnt += 2;
        }
        maxi = max(maxi, cnt);
    }
    cout << maxi << endl;
}