using System;

public class Program

{

    static void temp(string a){

        if(a==null){

        throw new ArgumentNullException();

        }

    }

    public static void Main()

    {

        try{

            string a = null;

            temp(a);

        }

        catch(ArgumentNullException a){

        }

        catch(Exception b){

        }

        Console.WriteLine("Hello World");

    }

}