#include <cstdio>

 int n;char ch;

 int p[];

 char a[];

 int min(int a,int b){return(a<b)?a:b;}

 int max(int a,int b){return(a>b)?a:b;}

 int get(int k){return (k&)?p[k]/*:(p[k]+)/*-;}

 void add(int i)

 {

     int u=i-p[i],v=i+p[i];

     while((a[u]==a[v]) && (u>) && (v<=n))

         u--,v++,p[i]++;

 }

 int main()

 {

     while((ch<'a' || ch>'z')&&(ch!=EOF)) ch=getchar();

     while(ch!=EOF)

     {

         n=;a[]='';

         for(;ch>='a' && ch<='z';ch=getchar())

             a[++n]=ch,a[++n]='';

         int id=;

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

         {

             if(i<id+p[id])

             {

                 p[i]=min(p[id*-i],id+p[id]-i);

                 if(i+p[i]==id+p[id])

                     add(i);

             }

             else

                 p[i]=,add(i);

             if(i+p[i]>p[id]+id)

                 id=i;

         }

         int ans=;

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

             ans=max(ans,get(i));

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

         while((ch<'a' || ch>'z')&&(ch!=EOF)) ch=getchar();

     }

     return ;

 }