using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        for(int i = 0; i <= 16; i++)

        {

           Console.WriteLine(string.Join("",Print(i, 4)));

        }

    }

    static int[] Print(int num, int length)

    {

        if(num >= (1 << length))

        {

            throw new ArgumentException(num + " is too big to be displayed in a binary output of length " + length);

        }

        int[] result = new int[length];

        for(int i = result.Length - 1; i >= 0; i--)

        {

            int powerOfTwo = 1 << i;

            int index = result.Length - i - 1;

            result[index] = num / powerOfTwo;

            num -= result[index] * powerOfTwo;

        }

        return result;

    }

}