#include <iostream>
#include <fstream>

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

ll manachers_algorithm(const string & s) {
    ll res = 0;

    string t = "^";
    for(char c: s) {
        t += "#";
        t += c;
    }
    t += "#$";

    int n = (int) t.length();
    vector<int> P(n, 0);
    int C = 0, R = 0;
    int max_length = 0, center_idx = 0;

    for(int i = 1; i < n - 1; i++) {
        int i_mirror = 2 * C - i;

        if(R > i) {
            P[i] = min(R - i, P[i_mirror]);
        }

        while(t[i + 1 + P[i]] == t[i - 1 - P[i]]) {
            P[i]++;
        }

        if(i + P[i] > R) {
            C = i;
            R = i + P[i];
        }

        if(P[i] > max_length) {
            max_length = P[i];
            center_idx = i;
        }

        res += (P[i] + 1) / 2;
    }
    return res;
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    string s;
    cin >> s;

    ll res = manachers_algorithm(s);
    int n = (int) s.size();

    for(int i = 0; i < n / 2; i++) {
        char orig = s[i];
        for(char c = 'a'; c <= 'z'; c++) {
            if(c == orig) continue;
            s[i] = c;
            res = max(res, manachers_algorithm(s));
        }
        s[i] = orig;
    }

    cout << res;
    return 0;
}