#include<iostream>
#include <bits/stdc++.h>
using namespace std;
char s[22000005];
char ss[22000005];
int p[22000005];
int lenss,lens,id=0,maxlen=0,maxn,cnt;
int main()
{
//	  freopen("calf.in","r",stdin);
//    freopen("calf.out","w",stdout);
    int i=0;
    while(scanf("%c",&s[i])!=EOF)
    {
        if(s[i]<=90&&s[i]>=65)
            ss[lenss++]=char(s[i]);
        else if(s[i]<=122&&s[i]>=97)
            ss[lenss++]=char(s[i]-32);
        i++;
    }
    for(int i=lenss; i>=0; --i) 
    {
        ss[i+i+2]=ss[i];
        ss[i+i+1]='#';
    }
    ss[0]='*';
    for(int i=2; i<2*lenss+1; ++i)
    {
        if(p[id]+id>i)p[i]=min(p[2*id-i],p[id]+id-i);
        else p[i]=1;
        while(ss[i-p[i]] == ss[i+p[i]])++p[i];
        if(id+p[id]<i+p[i])id=i;
        if(maxlen<p[i])
        {
            maxlen=p[i];
            maxn=i;
        }
    }
    cout<<maxlen-1<<endl;
    return 0;
}