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*/
#include <iostream>
#include <complex>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
#include <random>
using namespace std;
template<typename T1, typename T2>inline void chkmin(T1 &x, T2 y) { if (x > y) x = y; }
template<typename T1, typename T2>inline void chkmax(T1 &x, T2 y) { if (x < y) x = y; }
#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define left left224
#define right right224
#define next next224
#define rank rank224
#define prev prev224
#define y1 y1224
#define read(FILENAME) freopen((FILENAME + ".in").c_str(), "r", stdin)
#define write(FILENAME) freopen((FILENAME + ".out").c_str(), "w", stdout)
#define files(FILENAME) read(FILENAME), write(FILENAME)
#define pb push_back
#define mp make_pair
const string FILENAME = "input";
using ll = long long;
struct node{
node* CH[30];
node* bk;
int len, cnt;
} *n0, *n1;
bool cmp(node* X, node* Y){
return X -> len > Y -> len;
}
int n;
string s;
ll mx;
vector<node*> v;
void precompute() {
n1 = new node(); n0 = new node();
n1 -> len = -1, n0 -> len = 0;
n0 -> bk = n1; n1 -> bk = n1;
node* cur = n0;
for(int i = 0;i < n;i++){
for(; cur->len + 1 > i || s[i - cur->len - 1] != s[i]; cur = cur -> bk);
node *rmb = cur -> bk;
if(cur -> CH[s[i] - 'a'] == NULL)
cur -> CH[s[i] - 'a'] = new node(), v.pb(cur -> CH[s[i] - 'a']);
cur -> CH[s[i] - 'a'] -> len = cur -> len + 2;
cur = cur -> CH[s[i] - 'a'];
cur -> cnt++;
for(; rmb -> len + 1 > i || s[i - rmb->len - 1] != s[i]; rmb = rmb -> bk);
if(cur -> len == 1)
cur -> bk = n0;
else{
if(rmb -> CH[s[i] - 'a'] == NULL)
rmb -> CH[s[i] - 'a'] = new node(), v.pb(rmb -> CH[s[i] - 'a']);
cur -> bk = rmb -> CH[s[i] - 'a'];
}
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
//read(FILENAME);
cin >> s;
n = sz(s);
precompute();
sort(all(v), cmp);
for (auto &x: v) {
chkmax(mx, (ll)x -> len * x -> cnt);
x -> bk -> cnt += x -> cnt;
}
cout << mx << endl;
}
