using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

​

namespace ConsoleApp2

{

    internal class Program

    {

        static void Main(string[] args)

        {

start:      try

            {

                do

                {

             Console.WriteLine("Provide your mark");

                    int mark = Convert.ToInt32(Console.ReadLine());

​

                    switch (mark)

                    {

                        case 1:

                            Console.WriteLine("two");

                            break;

                        case 2:

                            Console.WriteLine("two");

                            break;

                        case 3:

                            Console.WriteLine("two");

                            break;

                        case 4:

                            Console.WriteLine("three");

                            break;

                        case 5:

                            Console.WriteLine("three");

                            break;

                        case 6:

                            Console.WriteLine("three");

                            break;

                        case 7:

                            Console.WriteLine("four");

                            break;

                        case 8:

                            Console.WriteLine("four");

                            break;

                        case 9:

                            Console.WriteLine("four");

                            break;

                        case 10:

                            Console.WriteLine("five");

                            break;

                        case 11:

                            Console.WriteLine("five");

                            break;

                        case 12:

                            Console.WriteLine("five");

                            break;

                        default:

                            Console.WriteLine("Not real");

                            break;

                    }

                } while (true);

            }

            catch (Exception eeerrr)

            {

                Console.WriteLine(eeerrr.Message);

                goto start;

            }

        }

    }

}