class Vessel {
   double contents;
}

class Tank extends Vessel {
  double length, width, height;

  Tank(double length, double width, double height) 
  { this.length = length; this.width = width; this.height = height; }
}

class Barrel extends Vessel {
  double radius, height;

  Barrel(double radius, double height) 
  { this.radius = radius; this.height = height; }
}

public class Vessel1 {
  public static void main(String[] args) {
    Tank tank1 = new Tank(15, 9, 12);
    Tank tank2 = new Tank(0.7, 0.7, 2.05);
    Barrel b1 = new Barrel(2.5, 8);

    tank1.contents = 700;
    System.out.println("Indhold af tank1 = " + tank1.contents);  
    System.out.println("Bredde af tank1  = " + tank1.width);  
    
    Vessel v1 = tank1;
    System.out.println("Indhold af v1 = " + v1.contents);  
  }
}