#include <bits/stdc++.h>

using namespace std;

long long int cnt1[31];
long long int cnt2[31];

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

	long long int a, b;

	memset(cnt1, 0, sizeof(cnt1));
	memset(cnt2, 0, sizeof(cnt2));

	a = 0;
	cin >> b;

	long long int t1, t2;
	for (int i = 0; i <= 30; i++)
	{
		long long int t = pow(2, i + 1);
		cnt1[i] = (b / t) * (t / 2);
		cnt2[i] = (a / t) * (t / 2);
		t2 = b % t;
		t1 = a % t;

		if (t2 >= t / 2)
		{
			cnt1[i] += (t2 - (t / 2) + 1);
		}
		if (t1 >= t / 2)
		{
			cnt2[i] += (t1 - (t / 2) + 1);
		}
	}

	for (int i = 0; i <= 30; i++)
	{
		//cout << i << ' ' << cnt1[i] << ' ' << cnt2[i] << '\n';
		cnt1[i] -= cnt2[i];
	}

	long long int res = 0;
	for (int i = 0; i <= 30; i++)
	{
		if (cnt1[i] % 2 == 1)
		{
			res += pow(2, i);
		}
	}

	if (res == 0)
	{
		cout << 'X' << '\n';
	}
	else
	{
		cout << 'O' << '\n';
	}
	
	return 0;
}