using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("What period are you in?");

        int myYear;

        try

        {

            myYear = Convert.ToInt16(Console.ReadLine());

        }

        catch

        {

            Console.WriteLine("you can only answer numbers");

            myYear=9;

        }

​

        switch (myYear)

        {

            case 1:

                Console.WriteLine("starts 9.10 ends 10:00");

                break;

            case 2:

                Console.WriteLine("starts 10.20 ends 11:20");

                break;

            case 3:

                Console.WriteLine("starts 11.50 ends 12:40");

                break;

            default:

                Console.WriteLine("i have no idea,sorry, try again later");

                break;

        }

    }

}