#include<cstdio>

 #include<cstring>

 #include<algorithm>

 using namespace std;

 const int N=,K=;

 int p[N],noww[N],goal[N];

 int rnk[N],bkt[N],mul[N][K];

 int trs[N][],fth[N],len[N],siz[N],num[N];

 char str[N>>],Str[N];

 int lth,lst,cnt,tot,mid,maxr;

 long long ans;

 void link(int f,int t)

 {

     noww[++cnt]=p[f];

     goal[cnt]=t,p[f]=cnt;

 }

 void DFS(int nde,int fth)

 {

     mul[nde][]=fth;

     for(int i=p[nde];i;i=noww[i])

         DFS(goal[i],nde),siz[nde]+=siz[goal[i]];

     for(int i=;mul[nde][i];i++)

         mul[nde][i]=mul[mul[nde][i-]][i-];

 }

 void Insert(int ch,int ps)

 {

     int nde=lst,newn=++tot;

     num[ps]=lst=newn,siz[newn]=,len[newn]=len[nde]+;

     while(nde&&!trs[nde][ch])

         trs[nde][ch]=newn,nde=fth[nde];

     if(!nde) fth[newn]=;

     else

     {

         int tran=trs[nde][ch];

         if(len[tran]==len[nde]+)

             fth[newn]=tran;

         else

         {

             int rnde=++tot; len[rnde]=len[nde]+;

             for(int i=;i<=;i++) trs[rnde][i]=trs[tran][i];

             fth[rnde]=fth[tran],fth[tran]=fth[newn]=rnde;

             while(nde&&trs[nde][ch]==tran)

                 trs[nde][ch]=rnde,nde=fth[nde];

         }

     }

 }

 void prework()

 {

     register int i,j;

     scanf("%s",str+),lth=strlen(str+),lst=tot=;

     for(i=;i<=lth;i++) Insert(str[i]-'a',i);

     for(i=;i<=tot;i++) link(fth[i],i); DFS(,);

 }

 void Solve(int l,int r)

 {

     l=(l+l%)/,r=(r-r%)/;

     if(l>r) return ;

     int nde=num[r],lth=r-l+;

     for(int i=;~i;i--)

         if(lth<=len[mul[nde][i]])

             nde=mul[nde][i];

     ans=max(ans,1ll*lth*siz[nde]);

 }

 void Manacher()

 {

     register int i;

     int newl=*lth+;

     for(i=;i<=newl;i++)

         Str[i]=(i&)?'?':str[i>>];

     Str[]='>',Str[newl+]='<';

     for(i=;i<=newl;i++)

     {

         fth[i]=(maxr>=i)?min(maxr-i+,fth[*mid-i]):;

         Solve(i-fth[i]+,i+fth[i]-);

         while(Str[i-fth[i]]==Str[i+fth[i]])

             fth[i]++,Solve(i-fth[i]+,i+fth[i]-);

         if(i+fth[i]->maxr) maxr=i+fth[i]-,mid=i;

     }

 }

 int main()

 {

     prework(),Manacher();

     printf("%lld",ans);

     return ;

 }