#include<algorithm>

 #include<iostream>

 #include<cstdlib>

 #include<cstring>

 #include<cstdio>

 using std::max;

 const int Max_N = ;

 char ret[Max_N];

 void solve() {

     int i, j, ans = , n = strlen(ret);

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

         for (j = ; i >= j && i + j < n; j++) {

             if (ret[i - j] != ret[i + j]) break;

             ans = max(ans, j <<  | );

         }

         for (j = ; i >= j && i + j +  < n; j++) {

             if (ret[i - j] != ret[i + j + ]) break;

             ans = max(ans, (j << ) + );

         }

     }

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

 }

 int main() {

 #ifdef LOCAL

     freopen("in.txt", "r", stdin);

     freopen("out.txt", "w+", stdout);

 #endif

     while (gets(ret)) solve();

     return ;

 }