//
//	Worksheet 9 #1
//

import java.text.DecimalFormat;	// p.18
import java.util.Scanner;
public class ComputeCircleArea
{
	public static void main(String[] args)
	{
		Scanner input = new Scanner(System.in);
		DecimalFormat f1 = new DecimalFormat("0.0");
		double radius, area;
		System.out.print("Input radius: ");
		radius = input.nextDouble();
		while(radius > 0)
		{
			area = Math.PI * radius * radius;
			System.out.println("Area = " + f1.format(area));
			System.out.print("Input radius: ");
			radius = input.nextDouble();
		}
	}
}