#include<iostream>

 #include<cstring>

 #include<cmath>

 #include<cstdio>

 #include<algorithm>

 using namespace std;

 const int N=;

 int n,tot,len[N],fail[N],s[N],last,to[N][],cnt[N];

 int L;

 long long ans;

 char ch[N];

 void init(){

     n=;tot=;

     len[]=;len[]=-;

     fail[]=;s[]=-;last=;

     memset(to,,sizeof(to));

 }

 void add(int c){

     s[++n]=c;

     int cur,now,tmp;

     for(cur=last;s[n-len[cur]-]!=c;cur=fail[cur]);

     if(!to[cur][c]){

         tot++;

         len[tot]=len[cur]+;now=tot;

         for(tmp=fail[cur];s[n-len[tmp]-]!=c;tmp=fail[tmp]);

         fail[now]=to[tmp][c];

         to[cur][c]=now;

     }

     last=to[cur][c];

     cnt[last]++;

 }

 void count(){

     for(int i=tot;i>=;i--){

         cnt[fail[i]]+=cnt[i];

         ans=max(1ll*cnt[i]*len[i],ans);

     }

 }

 int main(){

     scanf("%s",ch+);

     L=strlen(ch+);

     init();

     for(int i=;i<=L;i++)add(ch[i]-'a');

     count();

     printf("%lld",ans);

     return ;

 }