using System;

public class Program

{

    public static void Main()

    {

        Facede ff = new Facede();

        ff.MethodFirst();

        ff.MethodSecondy();

    }

}

​

public class SubSystemOne

{

    public void MethodOne()

    {

        Console.WriteLine("Method One");

    }

}

​

public class SubSystemTwo

{

    public void MethodTwo()

    {

        Console.WriteLine("Method Two");

    }   

}

​

public class SubSystemThree

{   

    public void MethodThree()

    {

        Console.WriteLine("Method Three");

    }

}

​

public class SubSystemFour

{

    public void MethodFour()

    {

        Console.WriteLine("Method Four");

    }

}

​

public class Facede

{

    private readonly SubSystemOne _one;

    private readonly SubSystemTwo _two;

    private readonly SubSystemThree _three;

    private readonly SubSystemFour _four;

    public Facede()

    {

        _one = new SubSystemOne();

        _two =  new SubSystemTwo();

        _three =  new SubSystemThree();

        _four =  new SubSystemFour();

    }

    public void MethodFirst()

    {

        Console.WriteLine("## First Step ##"); 

        _one.MethodOne();

        _two.MethodTwo();

        _four.MethodFour();

    }

    public void MethodSecondy()

    {

        Console.WriteLine("## Secondy Step ##"); 

        _two.MethodTwo();

        _three.MethodThree();

    }   

}