#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int MAXN=110000;
char s[MAXN+9],ma[MAXN*3+9];
int p[MAXN*3+9];
int manacher()
{
    int len=0;
    ma[len++]=‘$‘;
    ma[len++]=‘#‘;
    int n=strlen(s);
    for(int i=0;i<n;i++){
        ma[len++]=s[i];
        ma[len++]=‘#‘;
    }
    int ans=0;
    for(int i=0,mx=0,id=0;i<len;i++){
        p[i]=(mx>i?min(p[2*id-i],mx-i):1);//(id-(i-id))是i关于id对称的点
        while(ma[i+p[i]]==ma[i-p[i]]) p[i]++;
        if(i+p[i]>mx) mx=i+p[i],id=i;
        ans=max(ans,p[i]-1);
    }
    return ans;
}
int main()
{
    while(scanf("%s",s)==1){
        printf("%d\n",manacher());
    }
    return 0;
}