abstract class shape implements Comparable<shape>
{
    int x, y;
    double distance(shape other) {
        int dx = x-other.x, dy = y-other.y;
        return Math.sqrt(dx*dx + dy*dy);
    }
    public int compareTo(shape other) {
        int a = (int)(area()*1000+0.5);
        int b = (int)(area()*1000+0.5);
        return a-b;
    }
    abstract double area();
    abstract double circumference();
}//shape

class circle extends shape
{
    double radius;
    circle(int a, int b, int r) {x=a;y=b;radius=r;}
    double area() {return Math.PI*radius*radius;}
    double circumference() {return Math.PI*radius*2;}
}//circle

class rectangle extends shape
{
    double width, height;
    rectangle(int a, int b, double w, double h) {
        x=a; y=b; width=w; height=h;
    }
    double area() { return width*height; }
    double circumference() { return width*2 + height*2; }
}//rectangle

// ... triangle, etc

public class shapes2
{
    public static void main(String[] args) {
        shape S[] = new shape[4];
        S[0] = new circle(3,4,5);
        S[1] = new circle(50,60,10);
        S[2] = new rectangle(3,4,5,6);
        S[3] = new rectangle(30,40,50,60);
        double totalarea = 0;
        for(var c:S) totalarea+=c.area();
        System.out.printf("totalarea = %.2f\n",totalarea);
    }//main
}