using System;
class PruebaOcultamiento
{
    public class ClaseBase
    {
        public int x;
        
        public void Invocar ()
        {
            Console.WriteLine ("ClaseBase.Invocar");
        }
    }
    
    public class ClaseDerivada : ClaseBase
    {
        new public void Invocar ()
        {
            Console.WriteLine ("ClaseDerivada.Invocar");
        }
    }
    
    public static void Main ()
    {
        ClaseDerivada cd = new ClaseDerivada ();
        
        ClaseBase cb = cd;
        
        cb.Invocar();
    }
}