import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    String ans = "O";
    long t = 0;
    if(N % 4 == 1) t = N ^ (N - 1);
    if(N % 4 == 2) t = N ^ (N - 1) ^ (N - 2);
    if(N % 4 == 0) t = N; 
    if(t == 0) ans = "X";
    System.out.println(ans);
  }
}