using System;

public class Program

{

    public static void Main()

    {

        decimal sales =  0.0m;

        Console.WriteLine("What is the subtotal?");

        sales = Convert.ToDecimal(Console.ReadLine());

        string dayOfTheWeek;

        Console.WriteLine("What day of the week is it?");

        dayOfTheWeek = Console.ReadLine();

        switch (dayOfTheWeek)

        {

            case "Monday":

                sales *= .95m;

                sales *= 1.07m;

                break;

            case "Tuesday":

            case "Wednesday":

            case "Thursday":

            case "Friday":

                sales *= 1.07m;

                break;

            case "Saturday":

            case "Sunday":

                sales *= .80m;

                sales *= 1.07m;

                break;

            default:

                Console.WriteLine("This is not a real day");

                break;

        }

        Console.WriteLine("Your sales total for {0} is ${1:N2}", dayOfTheWeek, sales);

    }

}