public class Constructors {
  public static void main(String[] args) {
    System.out.println( new Cube(1,2,3).volume() );
  }
}

class Line {
  protected int width;
  public Line(int width) { this.width = width; }
}

class Square extends Line {
  protected int height;
  public Square(int width, int height) {
    super(width);
    this.height=height;
  }
}

class Cube extends Square {
  protected int depth;
  public Cube(int width, int height, int depth) {
    super(width,height);
    this.depth=depth;
  }
  public int volume() {
    return depth*height*width;
  }
}