#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 #include<queue>

 #include<map>

 #define bas 131

 #define bs 31

 #define p 1000000007

 #define p2 986598521

 #define ll long long

 #define N 1200005

 using namespace std;

 char c[N],s[N*];

 int hui[N],n;

 ll hash[N],pw[N],hash2[N],pw2[N];

 int head[],nxt[N],tot,len[N],size[N],zhi[N];

 ll key[N],key2[N],nx[N],nx2[N];

 void insert(ll x,ll xx,int l,ll z,int ss,ll ww)

 {

     int y=x%;

     tot++;nxt[tot]=head[y];head[y]=++tot;len[tot]=l;key[tot]=x;nx[tot]=z;zhi[tot]=ss;key2[tot]=xx;nx2[tot]=ww;

     return ;

 }

 int find(ll x,ll xx)

 {

     int y=x%;

     for(int i=head[y];i;i=nxt[i])

     {

         if(key[i]==x&&key2[i]==xx)return i;

     }

     return ;

 }

 int head2[N],ver2[N],nxt2[N],tot2;

 void add2(int x,int y)

 {

     tot2++;nxt2[tot2]=head2[x];head2[x]=tot2;ver2[tot2]=y;return ;

 }

 void manachar()

 {

     int mx=,id=;

     for(int i=;i<=n;i++)

     {

         if(i>mx)

         {

             hui[i]=;

             mx=i;id=i;

         }

         else

         {

             hui[i]=min(hui[id-(i-id)],mx-i+);

         }

         int l=i-hui[i],r=i+hui[i];

         while(l!=&&r!=n+&&s[l]==s[r])

         {

              hui[i]++;

              mx=i+hui[i]-;

              id=i;

              l--;r++;

         }

         int tmp=hui[i];

         if(s[i+hui[i]-]=='#')tmp--;

         if(tmp==)continue;

         int pos2=tmp+i-,pos1=i-tmp+;

         int lenn=(pos2-pos1)/+;

         ll haha,haha2;

         ll ha=(hash[pos2/]-(hash[pos1/-]*pw[lenn])%p+p)%p;

         ll ha2=(hash2[pos2/]-(hash2[pos1/-]*pw2[lenn])%p2+p2)%p2;

         if(pos2==pos1||pos2==pos1+)haha=,haha2=;

         else haha=(hash[pos2/-]-(hash[pos1/]*pw[lenn-])%p+p)%p,haha2=(hash2[pos2/-]-(hash2[pos1/]*pw2[lenn-])%p2+p2)%p2;

         int k=find(ha,ha2);

         if(!k)insert(ha,ha2,lenn,haha,pos2/,haha2),size[tot]++;

         else size[k]++;

     }

 }

 queue<int>qu;

 int ru[N];

 ll ans;

 void tupu()

 {

        for(int i=;i<=tot;i++)if(!ru[i])qu.push(i);

     while(!qu.empty())

     {

         int tmp=qu.front();qu.pop();

         ans=max(ans,(ll)size[tmp]*len[tmp]);

         for(int i=head2[tmp];i;i=nxt2[i])

         {

             ru[ver2[i]]--;

             size[ver2[i]]+=size[tmp];

             if(!ru[ver2[i]])qu.push(ver2[i]);

         }

     }

 }

 int main()

 {

     scanf("%s",c+);

     n=strlen(c+);

     pw[]=;pw2[]=;

     for(int i=;i<=n;i++)pw[i]=(pw[i-]*bas)%p;

     for(int i=;i<=n;i++)pw2[i]=(pw2[i-]*bs)%p2;

     for(int i=;i<=n;i++)hash[i]=(hash[i-]*bas+c[i]-'a'+)%p;

     for(int i=;i<=n;i++)hash2[i]=(hash2[i-]*bs+c[i]-'a'+)%p2;

     for(int i=;i<=n*+;i++)

     {

         if(i&)s[i]='#';

         else s[i]=c[i/];

     }

     n=n*+;

     manachar();

     for(int i=;i<=tot;i++)

     {

         if(nx[i]==)continue;

         int tmp=find(nx[i],nx2[i]);

         if(tmp!=)add2(i,tmp),ru[tmp]++;

         else

         {

             ll now,now2;

             if(len[i]<=)now=,now2=;

             else

             {

                 now=(hash[zhi[i]-]-(hash[zhi[i]-len[i]+]*pw[len[i]-])%p+p)%p;

                 now2=(hash2[zhi[i]-]-(hash2[zhi[i]-len[i]+]*pw2[len[i]-])%p2+p2)%p2;

             }

             insert(nx[i],nx2[i],len[i]-,now,zhi[i]-,now2);

             add2(i,tot);ru[tot]++;

         }

     }

     tupu();

     printf("%lld\n",ans);

     return ;

 }