#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#ifdef APURBA
#include "DEBUG_TEMPLATE.h"
#else
#define HERE
#define debug(args...)
#endif
typedef pair<int,int> pii;
#define ALL(x) x.begin(),x.end()
const int N = 3e5 +5;
const int oo = 1e9+7;
struct PalindromicTree {
struct node {
int nxt[26], len, st, en, link, diff, slink, cnt, oc;
};
string s;vector<node> t;
int sz, last;
PalindromicTree() {}
PalindromicTree(string _s) {
s = _s;
int n = s.size();
t.clear();
t.resize(n + 9);sz = 2, last = 2;
t[1].len = -1, t[1].link = 1;
t[2].len = 0, t[2].link = 1;
t[1].diff = t[2].diff = 0;
t[1].slink = 1;t[2].slink = 2;
}
int extend(int pos) { // returns 1 if it creates a new palindrome
int cur = last, curlen = 0;
int ch = s[pos] - 'a';
while (1) {curlen = t[cur].len;
if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos]) break;
cur = t[cur].link;
}
if (t[cur].nxt[ch]) {last = t[cur].nxt[ch];
t[last].oc++;
return 0;
}
sz++;last = sz;
t[sz].oc = 1;t[sz].len = t[cur].len + 2;
t[cur].nxt[ch] = sz;t[sz].en = pos;
t[sz].st = pos - t[sz].len + 1;
if (t[sz].len == 1) {
t[sz].link = 2;t[sz].cnt = 1;
t[sz].diff = 1;t[sz].slink = 2;
return 1;
}
while (1) {
cur = t[cur].link;curlen = t[cur].len;
if (pos - 1 - curlen >= 0 && s[pos - 1 - curlen] == s[pos]) {
t[sz].link = t[cur].nxt[ch];
break;
}
}
t[sz].cnt = 1 + t[t[sz].link].cnt;
t[sz].diff = t[sz].len - t[t[sz].link].len;
if (t[sz].diff == t[t[sz].link].diff) t[sz].slink = t[t[sz].link].slink;
else t[sz].slink = t[sz].link;
return 1;
}
void calc_occurrences() {
for (int i = sz; i >= 3; i--) t[t[i].link].oc += t[i].oc;
}
vector<array<int, 2>> minimum_partition() { //(even, odd), 1 indexed
int n = s.size();
vector<array<int, 2>> ans(n + 1, {0, 0}), series_ans(n + 5, {0, 0});
ans[0][1] = series_ans[2][1] = 1e9;
for (int i = 1; i <= n; i++) {
extend(i - 1);
for (int k = 0; k < 2; k++) {
ans[i][k] = 1e9;
for (int v = last; t[v].len > 0; v = t[v].slink) {
series_ans[v][!k] = ans[i - (t[t[v].slink].len + t[v].diff)][!k];
if (t[v].diff == t[t[v].link].diff) series_ans[v][!k] = min(series_ans[v][!k], series_ans[t[v].link][!k]);
ans[i][k] = min(ans[i][k], series_ans[v][!k] + 1);
}
}
}
return ans;
}
} t;
// int32_t main() {
// string s;cin >> s;
// PalindromicTree t(s);
// for (int i = 0; i < s.size(); i++) t.extend(i);
// t.calc_occurrences();
// long long ans = 0;
// for (int i = 3; i <= t.sz; i++) ans += t.t[i].oc;
// cout << ans << '\n';
// //auto ans = t.minimum_partition();
// // for (int i = 1; i <= s.size(); i++) {
// // cout << (ans[i][1] == 1e9 ? -1 : ans[i][1]) << ' ';
// // cout << (ans[i][0] == 1e9 ? -2 : ans[i][0]) << '\n';
// // }
// }
void solve()
{
string s;
cin>>s;
PalindromicTree t(s);
for(int i=0;i<s.size();i++)
{
t.extend(i);
}
t.calc_occurrences();
ll ans = 0;
for(int i=3;i<=t.sz;i++)
{
ans=max(ans, t.t[i].oc *1LL* t.t[i].len);
}
cout<<ans<<'\n';
}
/*
*/
int32_t main()
{
#ifndef APURBA
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
#endif
int T=1;
// cin>>T;
while(T--)
{
solve();
}
return 0;
}
