#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

bool check(const string &str){
   string tmp = str;
   reverse(tmp.begin(),tmp.end());
   if(str == tmp) return true;
   return false;
}

int main(){
   string s;
   cin >> s;
   int n = s.size();
   if(n == 2 || count(s.begin(),s.end(),s[0]) == n) cout << --n << endl;
   else{
      int ans = 1;
      for(int i = 0;i < n;i++) for(int j = 1;j <= n - i;j++) if(check(s.substr(i,j))) ans = max(ans,j);
      if(ans == n) ans -= 2;
      cout << ans << endl;
   }
}