#include<bits/stdc++.h>
#define L(i, j, k) for(int i = (j); i <= (k); ++i) 
#define R(i, j, k) for(int i = (j); i >= (k); --i) 
#define ll long long 
#define vi vector < int > 
#define sz(a) ((int) (a).size()) 
#define me(a, x) memset(a, x, sizeof(a)) 
using namespace std;
const int N = 2e6 + 7;
int n, m;
char s[N];

int p, ch[N][26], len[N], fa[N], lst, tot = 1;

int getfa(int x) {
	for(; p - len[x] - 1 < 1 || s[p - len[x] - 1] != s[p]; x = fa[x]) ;
	return x;
}

void ins() {
	lst = getfa(lst);
	if(!ch[lst][s[p] - 'a']) 
		++tot, 
		fa[tot] = ch[lst][s[p] - 'a'], 
		len[tot] = len[lst] + 2, 
		ch[lst][s[p] - 'a'] = tot;
	lst = ch[lst][s[p] - 'a'];
}
int cnt[N];

int main() {
	ios :: sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin >> (s + 1);
	n = strlen(s + 1);
	fa[0] = 1, len[1] = -1;
	L(i, 1, n) 
		p = i, ins(), cnt[lst] += 1;
	R(i, tot, 1) 
		cnt[fa[i]] += cnt[i];
	ll ns = 0;
	L(i, 2, tot)
		ns = max(ns, (ll) cnt[i] * len[i] * len[i]);
	cout << ns << '\n';
	return 0;
}