#include<iostream>
#include<string>
#include<vector>
using namespace std;
const int N = 300000 + 10;
int tree[N][26];
int idx, len[N], link[N], cnt[N], t;
string s;
long long oc[N];
void add(int p) {
while (s[p - len[t] - 1] != s[p])t = link[t];
int x = link[t];
int c = s[p] - 'a';
while (s[p - len[x] - 1] != s[p])x = link[x];
if (tree[t][c] == 0){
tree[t][c] = ++idx;
len[idx] = len[t] + 2;
link[idx] = len[idx] == 1 ? 2 : tree[x][c];
oc[idx]++;
}
else oc[tree[t][c]]++;
t = tree[t][c];
}
int main() {
len[1] = -1, link[1] = 1;
len[2] = 0, link[2] = 1;
idx = t = 2;
cin >> s;
s = '$' + s;
for (int i = 1; i < (int)s.size(); i++)add(i);
long long ans = 0;
vector<bool>fre(idx + 1, 0);
for (int i = idx; i >= 3; --i) {
oc[link[i]] += oc[i];
ans = max(ans, (1ll * len[i] * oc[i]));
}
cout << ans << "\n";
}
