#include<iostream>
#include<algorithm>
using namespace std;
long long n;
int main() {
	cin >> n; n++;
	for (int i = 0; i < 36; i++) {
		long long p = n / (1LL << (i + 1)); p *= (1LL << i);
		long long q = n % (1LL << (i + 1));
		p += max(0LL, q - (1LL << i));
		if (p % 2 == 1) { cout << "O" << endl; return 0; }
	}
	cout << "X" << endl;
	return 0;
}