using System;

public class Solution
{
    public static void Main()
    {
        var n = long.Parse(Console.ReadLine());
        var sum = (n * (n + 1)) / 2;
        while ((sum & 0x1) == 1)
        {
            sum >>= 1;
        }

        Console.WriteLine((sum == 0) ? "O" : "X");
    }
}