#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define sz size()
#define ff first
#define ss second
const int N = 1e5 + 5;
map <string, int> m;
string s;
int n, jog;
int main () {
// freopen ("polindrome.in", "r", stdin);
// freopen ("polindrome.out", "w", stdout);
// freopen ("input.txt", "r", stdin);
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> s;
int n = (int)s.sz;
string t;
for (int i = 0; i < n; ++i) {
t = "";
for (int j = i; j < n; ++j) {
t += s[j];
bool tr = 0;
for (int k = 0; k < (int)t.sz; ++k) {
if (t[k] != t[(int)t.sz - k - 1]) {
tr = 1;
// break;
}
}
if (!tr) {
m[t]++;
}
}
}
for (auto i : m) {
int x = (int)i.ff.sz;
int y = m[i.ff];
jog = max (jog, x * y);
}
cout << jog;
}
