02. Shopping List

using System;

namespace ShoppingList
{
    class Program
    {
        static void Main(string[] args)
        {
            var list = Console.ReadLine().Split('!').ToList();

            string input;

            while ((input = Console.ReadLine()) != "Go Shopping!")
            {
                var tokens = input.Split(' ');
                string command = tokens[0];
                string product = tokens[1];

                if (command == "Urgent" && !list.Contains(product))
                {
                    list.Insert(0, product);
                }
                else if (command == "Unnecessary" && list.Contains(product))
                {
                    list.Remove(product);
                }
                else if (command == "Correct" && list.Contains(product))
                {
                    string newProduct = tokens[2];
                    list[list.IndexOf(product)] = newProduct;
                }
                else if (command == "Rearrange" && list.Contains(product))
                {
                    list.Remove(product);
                    list.Add(product);
                }
            }

            Console.WriteLine(String.Join(", ", list));
        }
    }
}