using System;

using System.Threading;

public class Program 

{

    public static void Main()

    {

        Thread YY = new Thread (WriteY);

        Thread XX = new Thread (WriteX);

        XX.Start();

        YY.Start();     

    }

    static void WriteX()

    {

        for (int i = 0; i < 10000; i++) Console.Write ("X");    

    }

    static void WriteY()

    {

        for (int i = 0; i < 10000; i++) Console.Write ("Y");    

    }

}