#include <bits/stdc++.h>
typedef long long ll;
typedef unsigned long long int ull;
using namespace std;
const ll MOD = (ll)1e9+9;
int MAXN = 1e6;
//classes
//global
string str;
int n;
vector<ll> str_hash;
map<ll,ll> Map;
map<ll,int> Len;
void computeHash(){
ll m = 1e9+9;
ll p = 31;
ll pow_p = 1;
for(int i = 1; i <= n; i++){
str_hash[i] = (str_hash[i-1] + (str[i-1] - 'a'+1)*pow_p)%m;
pow_p = (pow_p*p)%m;
}
}
void sol(int left, int right){
while(left >= 0 && right < n){
if(str[left] != str[right]) return;
ll val = str_hash[right+1] - str_hash[left]*pow(31, right-left+1);
val = (val)%MOD;
Map[val]++;
Len[val] = right-left+1;
left--;
right++;
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
//ifstream fin("longpath.in");
//ofstream fout("longpath.out");
//stop
cin >> str;
n = str.length();
str_hash.resize(n+1);
computeHash();
for(int i = 0; i < n; i++){
sol(i, i);
sol(i, i+1);
}
ll ans = 0LL;
for(auto& i: Map){
//cout << i.first << " " << i.second << '\n';
ans = max(ans, i.second*Len[i.first]);
}
cout << ans << '\n';
return 0;
}
