using System;

​

public class Program

{

    public static void Main()

    {

        int r;

        double a;

        Console.WriteLine("Please enter the radius: ");

        r = Convert.ToInt32(Console.ReadLine());

        a = (3.14) * r * r;

        Console.WriteLine("The area of the circle is = ", a, "mm");

        Console.ReadLine();

    }

}