using System;

public interface IMessageOutput
{
	void Out(string message);
}

public class ConsoleMessageOutput : IMessageOutput
{
	public void Out(string message)
	{
		Console.WriteLine(message);
	}
}

public class ExtendedConsoleOutput : IMessageOutput
{
	public void Out(string message)
	{
		Console.WriteLine(DateTime.Now.ToString("HH:mm:ss") + " " + message);
	}
}

public class Worker
{
	private IMessageOutput _output;
	public Worker(IMessageOutput output)
	{
		_output = output;
	}
	
	public void DoWork()
	{
		for(int i = 0; i < 10; i++)
		{
			_output.Out("Counter: " + i);
		}
	}
}

public class Test
{
	public static void Main()
	{
		Worker worker = new Worker(new ConsoleMessageOutput());
		worker.DoWork();
		
		Worker worker2 = new Worker(new ExtendedConsoleOutput());
		worker2.DoWork();
		// your code goes here
	}
}