using System;

public class Test
{
	public static void Main()
	{
		IComputer computer = new KeyBoard(new Monitor(new Disk(new Computer())));

		Console.WriteLine(" You are getting a " + computer.getComputer());
	}
}

public interface IComputer
{
	string getComputer();
}

public sealed class Computer : IComputer
{
	public string getComputer()
	{
		return "computer";
	}
}

public abstract class ComputerDecorator : IComputer
{
	private IComputer _computer;
	public ComputerDecorator(IComputer computer)
	{
		_computer = computer;
	}
	
	public virtual string getComputer()
	{
		return _computer.getComputer();
	}
}

public class Disk : ComputerDecorator
{
	public Disk(IComputer c) : base(c)
	{
	}

	public override String getComputer()
	{
		return base.getComputer() + " and a disk";
	}
}

public class Monitor : ComputerDecorator
{
	public Monitor(IComputer c) : base(c)
	{
	}
	
	public override String getComputer()
	{
		return base.getComputer() + " and a Monitor";
	}
}

public class KeyBoard : ComputerDecorator
{
	public KeyBoard(IComputer c) : base(c)
	{
	}

	public override String getComputer()
	{
		return base.getComputer() + " and a KeyBoard";
	}
}