#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 3e5+111;
int n;
string s;
struct node{
int next[26];
int len;
ll num;
int suflink;
node(){
memset(next,255,sizeof(next));
}
};
node Tree[N];
int num, suf;
ll res;
vector<int> Adj[N];
void initTree(){
num = suf = 2;
Tree[1].len = -1; Tree[1].suflink = 1;
Tree[2].len = 0; Tree[2].suflink = 1;
}
void addLetter(int p){
int cur = suf, curlen = 0;
int x = s[p]-'a';
while(1){
curlen = Tree[cur].len;
if(p-curlen-1>=0&&s[p-curlen-1]==s[p]) break;
cur = Tree[cur].suflink;
}
if(Tree[cur].next[x]!=-1){
suf = Tree[cur].next[x];
Tree[Tree[cur].next[x]].num++;
return;
}
suf = ++num;
Tree[num].len = Tree[cur].len + 2;
Tree[cur].next[x] = num;
Tree[num].num = 1;
if(Tree[num].len==1){
Tree[num].suflink = 2;
Adj[2].push_back(num);
return;
}
while(1){
cur = Tree[cur].suflink;
curlen = Tree[cur].len;
if(p-curlen-1>=0&&s[p-curlen-1]==s[p]){
Tree[num].suflink = Tree[cur].next[x];
Adj[Tree[cur].next[x]].push_back(num);
break;
}
}
return;
}
void DFS(int u){
for(auto v: Adj[u]){
DFS(v);
Tree[u].num += Tree[v].num;
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>s;
n = s.size();
initTree();
for(int i = 0; i < n; i++){
addLetter(i);
}
DFS(1);
DFS(2);
for(int i = 3; i <= num; i++){
res = max(res,(ll)Tree[i].num*Tree[i].len);
}
cout<<res<<'\n';
return 0;
}
