abstract class Shape {
    abstract void area();

}

class Circle extends Shape {
    public double radius = 5.0 ;

    void area(){
        System.out.println(3.14*radius*radius);
    }
}

class Triangle extends Shape {
    public double height = 11.6 ;
    public double base = 7.8 ;
    void area(){
        System.out.println(1.0/2*base*height);
    }
}

public class Heart {
    public static void main (String[] args) {

    Shape c1=new Circle();
    Shape c2=new Triangle();
    c1.area();
    c2.area();


    }

}