using System;
using System.IO;

namespace Elementary_data_structures
{
    class Doubly_Linked_List
    {
        static void Main(string[] args)
        {
            var n = int.Parse(Console.ReadLine());
            var dllist = new DLinkedList<string>();
            for (int i = 0; i < n; i++)
            {
                var token = Console.ReadLine().Split(' ');
                switch (token[0])
                {
                    case "insert":
                        dllist.Insert(token[1]);
                        break;
                    case "delete":
                        dllist.Delete(token[1]);
                        break;
                    case "deleteFirst":
                        dllist.DeleteFirst();
                        break;
                    case "deleteLast":
                        dllist.DeleteLast();
                        break;
                }
            }
            dllist.Show();
        }

        public class DLinkedList<T>
        {
            public class Node
            {
                T key;
                public T Key { get { return key; } }
                public Node Prev { get; internal set; }
                public Node Next { get; internal set; }

                public Node(T key, Node prev, Node next)
                {
                    this.key = key;
                    Prev = prev;
                    Next = next;
                }
            }

            Node dummy;
            public Node First { get { return dummy.Next; } }
            public Node Last { get { return dummy.Prev; } }
            public Node EndOfList { get { return dummy; } }

            public DLinkedList()
            {
                dummy = new Node(default(T), null, null);
                dummy.Next = dummy;
                dummy.Prev = dummy;
            }

            public void Insert(T key)
            {
                Node n = new Node(key, dummy, First);
                First.Prev = n;
                dummy.Next = n;
            }

            public void DeleteNode(Node n)
            {
                if (n == dummy) return;
                n.Prev.Next = n.Next;
                n.Next.Prev = n.Prev;
                return;
            }

            public void Delete(T key)
            {
                for (Node n = First; n != EndOfList; n = n.Next)
                {
                    if (n.Key.Equals(key))
                    {
                        DeleteNode(n);
                        return;
                    }
                }
            }

            public void DeleteFirst()
            {
                DeleteNode(First);
            }

            public void DeleteLast()
            {
                DeleteNode(Last);
            }

            public void Show()
            {
                if (First == dummy) return;

                var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
                Console.SetOut(sw);

                Console.Write(First.Key.ToString());
                for (Node n = First.Next; n != EndOfList; n = n.Next)
                {
                    Console.Write(" " + n.Key.ToString());
                }
                Console.WriteLine();

                Console.Out.Flush();
            }
        }
    }
}

Measured memory_bytes: 137372