#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <set>
#include <map>
#include <numeric>
#include <regex>
#include <tuple>
#include <iomanip>
#include <cmath>
using namespace std;

typedef long long ll;
typedef pair<int, int> P;
#define MOD 1000000007 // 10^9 + 7
#define INF 1000000000 // 10^9
#define LLINF 1LL<<60


int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	
	ll N; cin >> N; N++;
	bool flag = true;

	if ((N / 2) % 2 == 1) {
		flag = false;
		//cout << "そもそも" << endl;
	}

	int num = 4;
	for (int i = 0; i < 35 && flag ; i++) {
		ll res = N % num;
		res = max(0LL, res - (num / 2));

		if (res % 2 == 1) {
			flag = false;
			//cout << num << endl;
		}
		num *= 2;
	}

	if (flag) cout << "X" << endl;
	else cout << "O" << endl;

	return 0;
}