02. Shopping List

using System;
using System.Collections.Generic;
using System.Linq;

namespace 02. Shopping List
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> products = Console.ReadLine().Split("!").ToList();
            while (true)
            {
                string[] command = Console.ReadLine().Split(" ", StringSplitOptions.RemoveEmptyEntries).ToArray();
                switch (command[0])
                {
                    case "Urgent":
                        urgent(products, command[1]);
                        break;
                    case "Unnecessary":
                        unnecessary(products, command[1]);
                        break;
                    case "Correct":
                        correct(products, command[1], command[2]);
                        break;
                    case "Rearrange":
                        rearrange(products, command[1]);
                        break;
                    case "Go":
                        Console.WriteLine(string.Join(", ", products));
                        return;
                }
            }
        }

        private static void rearrange(List<string> products, string item)
        {
            if (products.Contains(item))
            {
                products.Remove(item);
                products.Add(item);
            }
        }

        private static void correct(List<string> products, string oldItem, string newItem)
        {
            if (products.Contains(oldItem))
            {
                int index = products.IndexOf(oldItem);
                products.Remove(oldItem);
                products.Insert(index, newItem);
            }
        }

        private static void unnecessary(List<string> products, string item)
        {
            if (products.Contains(item))
            {
                products.Remove(item);
            }
        }

        private static void urgent(List<string> products, string item)
        {
            if (products.Contains(item))
            {
                return;
            }
            products.Insert(0,item);
        }
    }
}