#include<bits/stdc++.h>

using namespace std;

#define MAXN 110010

char s[MAXN];

inline void Manacher()

{

        int i,len,ans = ,pos = ,mx = ;

        static char tmp[MAXN<<];

        static int p[MAXN<<];

        len = strlen(s+);

        for (i = ; i <= len; i++)

        {

                tmp[*i-] = '#';

                tmp[*i] = s[i];

        }

        tmp[len =  * len + ] = '#';

        for (i = ; i <= len; i++)

        {

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

                else p[i] = ;

                while (i - p[i] >=  && i + p[i] <= len && tmp[i-p[i]] == tmp[i+p[i]]) p[i]++;

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

                {

                        mx = i + p[i] - ;

                        pos = i;

                }

        }

        for (i = ; i <= len; i++) ans = max(ans,p[i]-);

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

}

int main()

{

        while (scanf("%s",s+) != EOF) Manacher();        

        return ;

}