using System;

public class Program

{

    public static void Main()

    {

        string s;

        double radius, laukums ; 

        Console.WriteLine("R");

        s = Console.ReadLine();

        radius = double.Parse(s);   

        laukums = Math.PI*radius*radius ;

        Console.WriteLine("Atbilde"+ laukums);

        Console.ReadKey();

    }

}