using System;

public class Program

{

    public static void Main()

    {

        double distance,charge = 30.00;

        Console.Write("enter distance:");

        distance = Convert.ToDouble(Console.ReadLine());

        if (distance > 300)

        {

            charge = charge + ((distance - 300) / 300) * 5.00;

        }

        else if (distance % 300 != 0)

        {

            charge = charge + 5.00;

        }

        Console.WriteLine("your charge is " + "{0:0.00}",charge);

        Console.ReadLine();

    }

}