public class Point : Intf 
{
  public int x;
  public int y;
  public static int point_num = 0;
    
  public Point( int _x, int _y ) 
  {
    point_num++;
    x = _x;
    y = _y;
  }

  public Point() 
  {
    point_num++;
    x = 1;
    y = 1;
  }

  public override int abstract_method() 
  {
    return 1;
  }

  public void show() 
  {
    Console.WriteLine( "x= " + x + " y= " + y );
  }

  public static int PointStatistics()
  {
    return (point_num /* !!!!! + external.callback( 10 ) !!!! */);
  }
}
