public static void Remove_order(int client_id, string hotel_name, int room_number)
        {
            try
            {
                Client client = Client_management.Find_by_id(client_id);
                Hotel  hotel  = Hotel_management.Find(hotel_name);

                if (!Is_free(hotel_name, room_number))
                {
                    int i = 0;
                    while (i < hotel.approved_orders.Count)
                    {
                        Order order = hotel.approved_orders[i];

                        if (order.Room_number == room_number)
                        {
                            hotel.approved_orders[i] = null;
                            hotel.empty_rooms.Insert(room_number - 1, room_number);

                            order.Client = null;

                            break;
                        }
                    }
                }
                else
                {
                    Console.WriteLine("There is no such order request");
                }
            }
            catch
            {
                Console.WriteLine("ERROR");
            }
        }
        public static void Order_room(int client_id, string hotel_name, string phone_number)
        {
            try
            {
                Client client = Client_management.Find_by_id(client_id);
                Hotel  hotel  = Hotel_management.Find(hotel_name);

                foreach (Order order in hotel.order_requests)
                {
                    if (order.Phone_number_for_request == phone_number)
                    {
                        order.Id = Find_free_id(hotel);

                        hotel.order_requests.Remove(order);
                        hotel.approved_orders.Add(order);
                        hotel.empty_rooms.RemoveAt(order.Room_number - 1);

                        order.Client = client;

                        break;
                    }
                }
            }
            catch
            {
                Console.WriteLine("ERROR");
            }
        }