#include<cstdio>

#include<iostream>

#include<cstring>

#define M 220010

using namespace std;

char s,s1[M],s2[M];

int n,p[M];

void manacher()

{

    int id=,mx=,ans=;

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

    {

        if(mx>i)p[i]=min(p[*id-i],mx-i);

        else p[i]=;

        while(s2[i+p[i]]==s2[i-p[i]])++p[i];

        if(i+p[i]>mx)

        {

            id=i;

            mx=i+p[i];

        }

        ans=max(ans,p[i]-);

    }

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

}

void init()

{

    n=strlen(s1);

    s2[]='$';

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

      s2[*i+]='#',s2[*i+]=s1[i];

    manacher();

}

int main()

{

    while(scanf("%s",s1)!=EOF)

    {

        memset(p,,sizeof(p));

        memset(s2,,sizeof(s2));

        init();

    }

    return ;

}