#include <bits/stdc++.h>
using namespace std;
void just_do_it();
int main() {
#ifdef KAMIRULEZ
freopen("kamirulez.inp", "r", stdin);
freopen("kamirulez.out", "w", stdout);
#endif
ios_base::sync_with_stdio(0);
cin.tie(0);
just_do_it();
return 0;
}
struct node {
int len = 0;
node *ch[26] = {};
node *suf = nullptr;
vector<node*> ch_suf;
int cnt = 0;
node() {};
node(int _len): len(_len) {};
};
node *root0 = new node(0);
node *root1 = new node(-1);
const int maxn = 3e5 + 20;
int a[maxn];
long long res;
void dfs(node *u) {
for (auto v: u->ch_suf) {
dfs(v);
u->cnt += v->cnt;
}
res = max(res, 1LL * u->len * u->cnt);
}
void just_do_it() {
root0->suf = root1;
root1->suf = root1;
root1->ch_suf.push_back(root0);
string s;
cin >> s;
int n = s.size();
for (int i = 1; i <= n; i++) {
a[i] = s[i - 1] - 'a';
}
a[0] = -1;
node *cur = root0;
for (int i = 1; i <= n; i++) {
while (a[i - cur->len - 1] != a[i]) {
cur = cur->suf;
}
if (!cur->ch[a[i]]) {
cur->ch[a[i]] = new node(cur->len + 2);
if (cur == root1) {
cur->ch[a[i]]->suf = root0;
}
else {
node *cur_suf = cur->suf;
while (cur_suf->len > 0 && a[i - cur_suf->len - 1] != a[i]) {
cur_suf = cur_suf->suf;
}
cur->ch[a[i]]->suf = cur_suf->ch[a[i]];
}
cur->ch[a[i]]->suf->ch_suf.push_back(cur->ch[a[i]]);
}
cur = cur->ch[a[i]];
cur->cnt++;
}
dfs(root1);
cout << res;
}
