#include<cstdio>

#include<algorithm>

#include<cstring>

using namespace std;

const int maxn=;

int n,p[maxn];

char s[maxn],ss[maxn];

void manacher()

{

    int mx=,id=;

    int ans=;

    for(int i=;i<=n;i++)//$不管

     {

         if(i<mx)

          {

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

          }

         else p[i]=;

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

         if(i+p[i]->mx)

          {

              mx=i+p[i]-;

              id=i;

          }

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

     }

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

}

int main()

{

    while(scanf("%s",ss+)==)

     {

         int tot=strlen(ss+);

        n=;s[]='$';s[]='#';

        for(int i=;i<=tot;i++)s[++n]=ss[i],s[++n]='#';

        manacher();

     }

    return ;

}