import java.io.*;
import java.util.*;


public class Main_yukicoder524 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		long n = sc.nextLong();

		long ret = 0;
		if (n < 1_000_000) {
//		if (n < 10) {
			for (int i = 1; i <= n; i++) {
				ret ^= i;
//				pr.printf("%d %d\n", i, ret);
			}
		} else {
			for (int i = 1; true; i++) {
				long tmp = (0x1L << i + 1) - 1;
				if (tmp >= n) {
					n -= (0x1L << i) - 1;
					if (n % 4 == 0) {
						ret = 0;
					} else {
						ret = 1;
					}
					break;
				}
			}
		}

		if (ret != 0) {
			pr.println("O");
		} else {
			pr.println("X");
		}
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}