// Change program to read in the radius from the keyboard with Scanner


public class ComputeArea
{
   public static void main(String[] args)
   {
      double radius;
      double area;
      Spinner input = new Scanner(System.in); // (A) 

      // (1) Read in radius from System.in
      radius = input.nextDouble();            // (B)   (**) Compile -> error  

      // (2) Compute area
      area = 3.14159 * radius * radius;

      // (3) Print result
      System.out.println(area);
   }                       
}