import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
	
	public static long MOD = 1000000007;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final long N = sc.nextLong();
		
		for(long bit = 0; bit < 31; bit++){
			final long div = 1l << (bit + 1);
			final long inn = (N / div) * (div / 2);
			final long mod = N % div;
			
			final long count = inn + Math.max(0, (mod + 1) - (div / 2));
			
			if(count % 2 != 0){
				System.out.println("O");
				return;
			}
		}
		
		System.out.println("X");
	}
}