using System;

public class Program

{

    public static void Main()

    {

        int dayNumber;

        Console.WriteLine("Enter day number in the week:");

        string dayString = Console.ReadLine();

        bool dayParsed = int.TryParse(dayString, out dayNumber);

        switch (dayNumber)

        {

            case <0:

                Console.WriteLine("Error you entered a negative number");

                break;

            case >6:

                Console.WriteLine("Error you entered an invalid day in the week, retry [0..6]");

                break;

            case 0:

                Console.WriteLine("It is working day: Monday");

                break;

            case 1:

                Console.WriteLine("It is working day: Tuesday");

                break;

            case 2:

                Console.WriteLine("It is working day: Wednesday");

                break;

            case 3:

                Console.WriteLine("It is working day: Thursday");

                break;

            case 4:

                Console.WriteLine("It is working day: Friday");

                break;

            case 5:

                Console.WriteLine("It is a holiday: Saturday");

                break;

            case 6:

                Console.WriteLine("It is a holiday: Sunday");

                break;          

        }

    }

}