using System;

public class Program

{

    public static void Main()

    {

        A.Add(10,20, new[] {10,20,40});

    }

}

public class A

{

    public static void Add(int X, int Y)

    {

        A.Add(X, Y, null);

    }

    public static void Add(int X, int Y, int[] numbers)

    {

    int Sum = X + Y;

    if (numbers != null)

    {

        foreach(int i in numbers)

        {

            Sum += i;

        }

    }

        Console.WriteLine("Sum = {0}", Sum);

    }

}