using System;

public class Program

{

    public static void Main(string[] args)

    {

        Console.WriteLine("========================");

        Console.WriteLine("      R A D Y T A       ");

        Console.WriteLine("========================");

        float jari2;

        float pi;

        float keliling;

        pi = 3.14f;

        Console.WriteLine("masukkan jari jari lingkaran :");

        jari2 = float.Parse(Console.ReadLine());

        keliling = 2 * pi * jari2;

        Console.WriteLine("keliling lingkaran dengan jari-jari " + jari2 + " adalah " + keliling );

    }

}