using System;

​

abstract class Base {

    public abstract void Print(string msg);

}

​

class Printer : Base {

    public override void Print(string msg) {

        Console.WriteLine(msg);

    }

​

    public void Print(object obj) {

        throw new Exception("DONT CALL ME!");

    }

}

public class Program

{

    public static void Main()

    {

        var pr = new Printer();

        // call Print(object)

        //pr.Print((object)"Hello");

        // call Print(string)

        pr.Print((string)"Hello");

    }

}