import java.awt.*;

abstract class Vessel {
  double contents;

  abstract double volume();

  abstract double circumf();

  public void fill(double amount) {
    contents = contents + amount;
    contents = Math.min(contents, volume());
  }
}

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

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

  double volume() { 
    return length * width * height; 
  }

  double circumf() {
    return 2 * (width + length);
  }

  public String toString() {
    return "Tank med indhold: " + contents;
  }
}

class Barrel extends Vessel {
  double radius, height;

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

  double volume() { 
    return height * Math.PI * radius * radius; 
  }

  double circumf() {
    return 2 * Math.PI * radius;
  }

  public String toString() {
    return "Tønde med indhold: " + contents;
  }
}

interface Colored {
  Color getColor();
}

class ColoredBarrel extends Barrel implements Colored {
  private Color c;

  ColoredBarrel(double radius, double height, Color c) { 
    super(radius, height); this.c = c; 
  }

  public Color getColor() { 
    return c; 
  }
}

public class Vessel11 {
  static void printColor(Colored cobj) { 
    System.out.println(cobj.getColor().toString()); 
  }

  public static void main(String[] args) {
    Barrel b = new Barrel(15, 9);
    ColoredBarrel cb = new ColoredBarrel(2.5, 8, Color.red);

    printColor(cb);
    //    printColor(b); Denne ordre kan ikke oversættes, da b ikke implementerer Colored.
  }
}