#include <bits/stdc++.h>
#define NN 300000
#define pb push_back
typedef int ll;
using namespace std;
long long ans;
struct pal{
ll cnt;
pal *a[26];
pal *b[20];
ll h;
}*root=new pal(),*root1=new pal();
pal *u,*ptr[NN];
void ins(pal *rt,ll k){
if(rt->a[k]==NULL){
rt->a[k]=new pal();
/*for(ll i=0;i<20;i++){
(rt->a[k])->b[i]=new pal();
}
(rt->a[k])->b[0]=rt;
for(ll i=1;i<20;i++){
(rt->a[k])->b[i]=((rt->a[k])->b[i-1])->b[i-1];
}
(rt->a[k])->h=(rt->h)+1;*/
}
u=rt->a[k];
}
int solve(pal *rt,ll length,bool b){
for(ll i=0;i<26;i++){
if(rt->a[i]!=NULL){
rt->cnt+=(solve(rt->a[i],length+1,b));
}
}
ans=max(ans,(long long)((long long)(rt->cnt)*(long long)(b==1?(length*2-1):(length*2))));
int o=rt->cnt;
delete(rt);
rt=NULL;
return o;
}
int main(){
for(ll i=0;i<20;i++){
root->b[i]=new pal();
root->b[i]=root;
}
string s;
cin >> s;
ll n=s.size();
vector<ll>d1(n);
for (ll i = 0, l = 0, r = -1; i < n; i++) {
ll k = (i > r) ? 1 : min(d1[l + r - i], r - i + 1);
if(r>=i){
if(d1[l+r-i]<=(r-i+1)){
u=ptr[l+r-i];
}
else{
u=ptr[l+r-i];
for(ll j=19;j>=0;j--){
if(((u->b[j])->h)>=(r-i+1)){
u=u->b[j];
}
}
}
}
else ins(root,(s[i]-'a'));
while (0 <= i - k && i + k < n && s[i - k] == s[i + k]){
ins(u,(s[i-k]-'a'));
k++;
}
d1[i] = k--;
// ptr[i]=u;
// (u->cnt)++;
if (i + k > r) {
l = i - k;
r = i + k;
}
}
solve(root,0,1);
/*for(ll i=0;i<20;i++){
root1->b[i]=new pal();
root1->b[i]=root1;
}
vector<ll>d2(n);
for(ll i=0,l=0,r=-1;i<n;i++){
ll k=((i>r)?0:min(d2[l+r-i+1],r-i+1));
if(r>=i){
if(d2[l+r-i+1]<=r-i+1){
u=ptr[l+r-i+1];
}
else{
u=ptr[l+r-i+1];
for(ll j=19;j>=0;j--){
if(((u->b[j])->h)>=(r-i+1)){
u=u->b[j];
}
}
}
}
else u=root1;
while(0<=i-k-1 && i+k<n && s[i-k-1]==s[i+k]){
ins(u,(s[i+k]-'a'));
k++;
}
d2[i]=k--;
ptr[i]=u;
(u->cnt)++;
if(i+k>r){
l=i-k-1;
r=i+k;
}
}
solve(root1,0,0);*/
cout << ans;
}
