using System;

public class Program

{

    public static void Main()

    {

        double radius ;

        Console.WriteLine(" Enter the radius ");

        radius = double.Parse(Console.ReadLine());

        double PI ;

        PI = 3.14 ;

        double A; 

        A= PI * radius * radius;

        Console.WriteLine(" the area equal "+ A);

        Console.WriteLine("              thank you ");

    }

}