// Arup Guha
// 7/7/03
// Short program with input/output that allows user to choose the size of
// the radius of the circle. The program then outputs the area of this
// circle.

import java.util.*;

public class Circle2 {

	public static void main(String[] args) {

		// Declare necessary reading object.
		Scanner stdin = new Scanner(System.in);

		// Get size of radius from user.
		int radius;
		System.out.println("What is the radius of your pizza?");
		radius = stdin.nextInt();

		// Compute and print out area.
		double area = Math.PI*radius*radius;
		System.out.print("The area of your pizza with radius "+radius);
		System.out.println(" is "+area);
	}
}