#define FOR(i,j,n) for (int i=(j);i<(n);i++)
#define REP(i,n) for (int i=0;i<(n);i++)
#include <bits/stdc++.h>
using namespace std;
string s;
int i,j,t,ret,tmp;

int main(){
    cin >> s;
    t = s.size();
    REP(ti,t){ FOR(tj,ti,t) {
        i = ti; j = tj; tmp = 0;
        while (i <= j){
            if (s[i] == s[j]){
                tmp += i == j ? 1 : 2;
            }
            i++; j--;
        }
        ret = max(ret,tmp);
    } }
    cout << ret << endl;
}