#include <bits/stdc++.h>

 using namespace std;

 typedef long long ll;

 inline ll read(){

     int x = , f = ; char ch = getchar();

     while(ch > '' || ch < ''){if (ch == '-') f = -; ch = getchar();}

     while(ch >= '' && ch <= ''){ x = x*+ch-''; ch = getchar();}

     return x*f;

 }

 /************************************************************************/

 const int maxn = 1e6+;

 char s[maxn];

 char str[maxn];

 int dp1[maxn], p[maxn];

 int dp2[maxn];

 int len;

 void manacher(char s[], int len){

     int ans = ;

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

         str[i<<] = s[i];

         str[(i<<)+] = '#';

     }

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

     str[] = '&'; str[len*+] = '$';

     len = len*+;

     int j = , k;

     for(int i = ;i <= len;){

         while(str[i-j-] == str[i+j+]) j++;

         p[i] = j;

         if(j > ans) ans = j;

         for(k = ;k <= j && (p[i]-k != p[i-k]);k++){

             p[i+k] = min(p[i-k], p[i] - k);

         }

         i += k;

         j = max(j-k, );

     }

 }

 int main(){

     scanf("%s", s+);

     len = strlen(s+);

     manacher(s, len);

     len = len*+;

     cout << "str: " << str << endl;

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

         for(int j = p[i];j >= ;j--){

             if(dp1[i+j] >= j) break;

             dp1[i+j] = j;

         }

         for(int j = p[i];j >= ;j--){

             if(dp2[i-j] >= j) break;

             dp2[i-j] = j;

         }

     }

     int ans = ;

     for(int i = ;i <= len-;i++){

         if(dp1[i] && dp2[i])

             ans = max(ans, dp1[i] + dp2[i]);

     }

     cout << ans << endl;

     return ;

 }