using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var itemslist = new List<string>() { "Chicken", "Duck" };

        int option;

        while(true)

        {

            Console.WriteLine("Shopping list:\n1. Add to list\n2. Remove from list\n3. List the items on the shopping list\n4. Exit");

            option = Convert.ToInt32(Console.ReadLine());

            if(option == 1)

            {

                Console.WriteLine("\nWhat would you like to add to the list?\nType nothing to exit\n*NOTE* You can only add one item at a time");

                string itemtoadd = Console.ReadLine();

                if(itemtoadd == "null" || itemtoadd == "")

                {

                    Console.WriteLine("Nothing was added to the list");

                }

                else

                {

                    itemslist.Add(itemtoadd);

                    Console.WriteLine(itemtoadd + " was added to the list");

                }

            }

            else if(option == 2)

            {

                Console.WriteLine("\nWhat would you like to remove from the list?\n*NOTE* You can only add one item at a time");

                string itemtoremove = Console.ReadLine();

                if(itemtoremove == "" || itemtoremove == "null")

                {

                }

                else

                {

                    itemslist.Remove(itemtoremove);

                    Console.WriteLine(itemtoremove + " was removed from the list");

                }

            }

            else if(option == 3)

            {

                foreach(string item in itemslist)

                {

                    Console.WriteLine(item);

                }

            }

            else if(option == 4)

            {

                break;

            }

            else

            {

                Console.WriteLine("\nPlease enter a valid option:");

            }

        }

    }

}