#include <iostream>
#include <vector>
#include <algorithm>
#include <cstring>
#include <map>
using namespace std;
typedef long long ll;

string S;

ll count_palindromes(const string & s) {
    ll res = 0;
    for(int i = 0; i < (int) s.size(); i++) {
        string tmp = "";
        for(int j = i; j < (int) s.size(); j++) {
            tmp += s[j];
            int S = 0, E = (int) tmp.size() - 1;
            bool ok = true;
            while(S < E) {
                if(tmp[S] != tmp[E]) {
                    ok = false;
                    break;
                }
                S++;
                E--;
            }
            if(ok) {
                res++;
            }
        }
    }
    return res;
}
int main() {
    ios_base::sync_with_stdio(false);
    cin >> S;
    vector<char> c;
    vector<bool> visited(26, false);
    for(char x: S) {
        if(!visited[x - 'a']) {
            c.push_back(x);
            visited[x - 'a'] = true;
        }
    }
    ll res = 0;
    for(int i = 0; i < (int) S.size(); i++) {
        string tmp = S;
        for(char x: c) {
            tmp[i] = x;
            res = max(res, count_palindromes(tmp));
        }
    }
    cout << res << endl;


    return 0;
}