using System;

public class Program

{

    public static void Main()

    {

        int Totalcost = 0;

        start:

        Console.WriteLine("which coffee will u prefer 1:small 2:regular 3:large");

        int userchoice=int.Parse(Console.ReadLine());

​

        switch(userchoice)

        {

            case 1:Totalcost+=1;

                break;

            case 2:Totalcost+=2;

                break;

            case 3:Totalcost+=3;

                break;

            default :   

                Console.WriteLine("your choice  {0} is invalid",userchoice);

                break;

        }

    decide:

        Console.WriteLine("do u need anything else-yes or no?");

        String choice=Console.ReadLine();

        switch(choice.ToUpper())

        {

            case "YES":

            goto start;

            case "NO":

                break;

            default:

                Console.WriteLine("enter a valid choice");

         goto decide;

        }

        Console.WriteLine("Thank you for shopping with us");

        Console.WriteLine(" your bill amount is {0}",Totalcost);

    }

}