//extending interface
interface value{
	final static float p=3.142F;
}
interface Areas extends value{
	float calculate(float x);
}
class circle implements Areas{
	public float calculate(float x) {
		return x*x*p;
	}
	
}
public class assign11{
	public static void main(String args[]){
			circle cr=new  circle();
			float x=cr.calculate(5);
			System.out.println("Area of circle:" +x);
		}
	}