#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(v) v.begin(),v.end()
using ll=long long int;
using pii=pair<int,int>;
using pdd=pair<double,double>;
const int mod=1000000000+7;
const int inf=1000000;


int main(){
    ll N;
    cin >> N;
    if(N%4==3)cout << "X" << endl;
    else cout << "O" << endl;
    return 0;
}