#include<iostream>
using namespace std;
using ll = long long;
#define forn(i, n) for(int i=0; i<(int)n; ++i)
#define forsn(i, s, n) for(int i=s; i<(int)n; ++i)
#define dforn(i, n) for(int i=n-1; i>=0; --i)
struct trie{
int cnt=0, total=0;
trie *up[21], *nxt[28]={0};
};
const int MAXN=600015;
int n, l=1, r=1, len[MAXN];
ll ans;
trie *root, *pal[MAXN];
string str, aux;
void dfs(trie* v, int d, bool yes){
v->total=v->cnt;
forn(i, 28) if(v->nxt[i]){
dfs(v->nxt[i], d+1, yes^1);
v->total+=v->nxt[i]->total;
}
if(yes) ans=max(ans, ((ll)d)*v->total);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> aux;
str.resize(2*aux.size() + 1);
str[0]='$';
forn(i, aux.size()) str[2*i+1]=aux[i];
forn(i, aux.size()-1) str[2*i + 2]='z'+1;
str.back()='^';
n = str.size();
root = new trie;
forn(i, 21) root->up[i]=root;
forsn(i, 1, n-1){
trie* cur=NULL;
if(i>=r) cur=root;
else{
len[i]=min(r-i, len[l+r-i]);
cur=pal[l+r-i];
int goUp=len[l+r-i]-len[i];
dforn(j, 21) if(goUp>=(1<<j)) goUp-=(1<<j), cur=cur->up[j];
}
while(str[i+len[i]]==str[i-len[i]]){
int pos=str[i+len[i]]-'a';
++len[i];
if(cur->nxt[pos]==NULL){
cur->nxt[pos]=new trie;
trie** ptr=cur->nxt[pos]->up;
ptr[0]=cur;
forn(j, 20) ptr[j+1]=ptr[j]->up[j];
}
cur=cur->nxt[pos];
}
if(i+len[i]>r) r=i+len[i], l=i-len[i];
pal[i]=cur;
cur->cnt++;
}
forn(i, 26) if(root->nxt[i]) dfs(root->nxt[i], 1, true);
if(root->nxt[26]) dfs(root->nxt[26], 1, false);
cout << ans << '\n';
}
