#include <bits/stdc++.h>
using namespace std;

int calc(int m, const string & S){
    int ans = 1;
    for (int a = m - 1, b = m + 1; a >= 0 and b < S.size(); --a, ++b){
        if (S[a] == S[b]) ans += 2;
    }
    return ans;
}

int calc2(int n, const string & S){
    int ans = 0;
    for (int a = n, b = n + 1; a >= 0 and b < S.size(); --a, ++b){
        if (S[a] == S[b]) ans += 2;
    }
    return ans;
}

int main(){
    string S;
    cin >> S;
    int ans = 0;
    for (int m = 0; m < S.size(); ++m){
        ans = max(ans, calc(m, S));
    }
    for (int n = 0; n + 1 < S.size(); ++n){
        ans = max(ans, calc2(n, S));
    }
    cout << ans << endl;
    return 0;
}