//import Scanner class
import java.util.Scanner;
 
// the name of our class is public
public class CircleArea {
//void main
  public static void main (String[] args)
  {
   //declare double
    double r;  // GIVEN : the radiusn of the circle
    double area ; // RESULT
    
   // print message
    System.out.println("Enter Radius:");
   // take input
    Scanner keyboard = new Scanner(System.in);
    r = keyboard.nextDouble();

   // algorithm
   area = 3.142 * r * r;
   
   //print the result
   System.out.println("Area = " + area);
 }
}