using System;
using System.IO;
using System.Linq;
using System.Collections.Generic;

public class Program
{

	public void Proc()
	{
        IsWin.Add(1, true);
        IsWin.Add(2, true);
        IsWin.Add(3, false);
        IsWin.Add(4, true);
        int num = int.Parse(Reader.ReadLine());
        if(num >= 5) {
            Console.WriteLine("O");
        } else {
            Console.WriteLine(IsWin[num]?"O":"X");
        }
	}



    Dictionary<int, bool> IsWin = new Dictionary<int, bool>();

	public class Reader
	{
		private static StringReader sr;
		public static bool IsDebug = false;
		public static string ReadLine()
		{
			if (IsDebug)
			{
				if (sr == null)
				{
					sr = new StringReader(InputText.Trim());
				}
				return sr.ReadLine();
			}
			else
			{
				return Console.ReadLine();
			}
		}
		private static string InputText = @"

3



";
	}

	public static void Main(string[] args)
	{
#if DEBUG
		Reader.IsDebug = true;
#endif
		Program prg = new Program();
		prg.Proc();
	}
}