interface Area {
	
	final static float pi=3.14f;
	float compute(float x,float y);
}

class Rectangle implements Area {
	
	public float compute(float x,float y) {
		
		return(x*y);
	}
}

class Circle implements Area {
	
	public float compute(float x,float y) {
		
		return(pi*x*y);
	}
}

public class InterfaceTest {
	
	public static void main (String[] args) {
		
		Rectangle rect = new Rectangle();
		Circle cir = new Circle();
		Area area;
		area = rect;
		System.out.println("Area of Recatngle = "+area.compute(10,20));
		area = cir;
		System.out.println("Area of Circle = "+area.compute(10,10));
	}
}