#include<bits/stdc++.h>
#define ll long long
using namespace std;
// PALINDROMIC TREE!
struct node{
ll next[26];
ll length;
ll link;
ll cnt;
};
vector<node> t(300001);
ll sz=2,last=0;
string s;
ll getlink(ll v,ll pos){
while(pos-1-t[v].length<0 or s[pos-1-t[v].length]!=s[pos]){
v=t[v].link;
}
return v;
}
void update(ll pos){
ll u=getlink(last,pos);
ll c=s[pos]-'a';
if(t[u].next[c]==0){
t[sz].length=t[u].length+2;
if(t[sz].length==1) t[sz].link=0;
else t[sz].link=t[(getlink(t[u].link,pos))].next[c];
t[u].next[c]=sz;
sz++;
}
last=t[u].next[c];
t[last].cnt++;
}
int main(){
ll n,i,j,k,q;
cin>>s;
n=s.size();
t[0].length=0;
t[0].link=1;
t[1].length=-1;
t[1].link=1;
for(i=0 ; i<n ; i++) update(i);
ll ans=0;
for(i=sz-1 ; i>=2 ; i--){
t[t[i].link].cnt+=t[i].cnt;
ans=max(ans,t[i].cnt*t[i].length);
}
cout<<ans<<"\n";
return 0;
}
