#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
#define all(x) (x).begin(),(x).end()
#define X first
#define Y second
#define sep ' '
#define endl '\n'
#define SZ(x) ll(x.size())
const ll MAXN = 3e5 + 10;
const ll LOG = 26;
const ll INF = 8e18;
const ll MOD = 1e9 + 7; //998244353; //1e9 + 9;
int n , palPrv , nxt[MAXN][LOG] , par[MAXN] , len[MAXN] , val[MAXN];
ll ans = 0;
vector<int> adj[MAXN];
string s;
void DFS(int v){
for(int u : adj[v]){
// cout << v << sep << u << endl;
DFS(u);
val[v] += val[u];
}
ans = max(ans , 1ll * val[v] * len[v]);
}
int main() {
ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
cin >> s; n = SZ(s);
len[0] = -1; len[1] = 0;
par[1] = 0; palPrv = 1;
adj[0].push_back(1);
for(int i = 0 ; i < n ; i++){
int prv = palPrv , ch = s[i] - 97;
// cout << i << sep << prv << endl;
while(1){
int k = len[prv];
// cout << i << sep << prv << sep << k << endl;
if(0 <= i - k - 1 && s[i] == s[i - k - 1]) break;
prv = par[prv];
}
// cout << i << sep << prv << endl;
if(nxt[prv][ch] != 0){
palPrv = nxt[prv][ch];
val[palPrv]++;
continue;
}
int cur = i + 2;
//cout << prv << sep << cur << endl;
palPrv = cur; val[cur]++;
nxt[prv][ch] = cur;
len[cur] = len[prv] + 2;
if(len[cur] == 1){
par[cur] = 1;
adj[1].push_back(cur);
continue;
}
while(1){
prv = par[prv];
int k = len[prv];
if(0 <= i - k - 1 && s[i] == s[i - k - 1]) break;
}
par[cur] = nxt[prv][ch];
adj[nxt[prv][ch]].push_back(cur);
}
DFS(0);
cout << ans << endl;
return 0;
}
/*
*/
