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

long long N;

int main() {
    cin >> N;
    long long a = (N / 4) * 4;
    long long sum = 0;
    for (long long i = a; i <= N; i++) {
        sum ^= i;
    }
    if (sum == 0) {
        cout << "X" << endl;
    } else {
        cout << "O" << endl;
    }
    return 0;
}