#include <bits/stdc++.h>
#define f first
#define s second
#define ent '\n'
#define int long long
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
//typedef long double ld;
typedef long long ll;
using namespace std;
struct node{double x,y;};
//double len(node a,node b)
//{return sqrt((a.x-b.x)*(a.x-b.y)+(a.y-b.y)*(a.x-b.y));}
struct seg{
int mx1=0,mx2=0,ans=0;
};
const string out[2]={"NO\n","YES\n"};
const ll dx[]={0,0,1,-1,-1,1,1,-1};
const ll dy[]={1,-1,0,0,-1,1,-1,1};
const int md=998244353;
const int mod=1e9+9;
const int mx=1e6+12;
const int tst=1e5;
const bool T=0;
int h[2012][2012];
int q[mx];
int n,m,k;
void Press_Fn_with_F11(){
string s;
cin>>s;
n=s.size();
s='+'+s;
map<int,int> cnt;
for(int i=1;i<=n;i++){
for(int j=i;j<=n;j++)h[i][j]=(h[i][j-1]*43+s[j]-'a'+1)%mod,cnt[h[i][j]]++;
}
int ans=0;
for(int i=1;i<=n;i++){
for(int l=i,r=i;l && r<=n && s[l]==s[r];l--,r++)ans=max(ans,cnt[h[l][r]]*(r-l+1));
if(i>1){
for(int l=i-1,r=i;l && r<=n && s[l]==s[r];l--,r++)ans=max(ans,cnt[h[l][r]]*(r-l+1));
}
}
cout<<ans<<ent;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
srand(time(0));
int Ersayin_abi_crush=1;
if(T)cin>>Ersayin_abi_crush;
for(int i=1;i<=Ersayin_abi_crush;i++){
// cout<<"Case "<<i<<": ";
Press_Fn_with_F11();
}
}
