#include <bits/stdc++.h>
using namespace std;

using ll = long long;
ll N;

int main() {
    cin >> N;

    if (N % 4 == 3) {  // 後手必勝
        cout << "X" << endl;
    } else {  // 先手必勝
        cout << "O" << endl;
    }

    return 0;
}