using System;

class A {
  public void          M( ){Console.WriteLine("M in A");}
  public virtual void  N( ){Console.WriteLine("N in A");}
  public virtual void  O( ){Console.WriteLine("O in A");}
  public void          P( ){Console.WriteLine("P in A");}
}

class B: A{
  public void          M( ){Console.WriteLine("M in B");} // warning
  public override void N( ){Console.WriteLine("N in B");}
  public void          O( ){Console.WriteLine("O in B");} // warning
  public new void      P( ){Console.WriteLine("P in B");}
}

class Client {
  public static void Main(){
    A aa = new A( ),     // aa has static type A, and dynamic type A
      ab = new B( );     // ab has static type A, and dynamic type B
    B b = new B( );      // b  has static type B, and dynamic type B

    aa.N( );   ab.N( );   b.N( );    // The dynamic type controls
    Console.WriteLine( );
    aa.P( );   ab.P( );   b.P( );    // The static type controls
  }
}