#include<iostream>
#include<string>

using namespace std;

bool cheack(string s){
	for (int i = 0; i < s.size() / 2; i++){
		if (s[i] != s[s.size() - 1 - i]) return false;
	}
	return true;
}

int main(){
	
	string s;
	cin >> s;

	for (int i = s.size()-1;; i--){
		for (int j = 0; j < s.size() - i + 1; j++){
			string s2 = "";
			for (int k = j; k < j + i; k++){
				s2 += s[k];
			}
			if (cheack(s2)){
				cout << i << endl;
				return 0;
			}
		}
	}
}