using System;

namespace a
{
	class Program
	{
		public static void Main(string[] args)
		{
			
			Console.ReadKey();
		}
	}
	
	public abstract class Logger {
		public abstract void Write (string s){
		
		}
		
		public virtual void GetVersion() {
			return "LoggerBase 1.0";
		}
	}
	
	class NormalLogger {
		
	}
	
	class ColorLogger {
	
	}
	
	class LoggerService {
		
	}
}