public static void RemoveOrder(ref RestaurantManager restaurantManager)
{
Console.WriteLine("Enter the number you want to delete:");
string removeStr = Console.ReadLine();
int remove;
while (!int.TryParse(removeStr, out remove) || remove < 0)
{
Console.WriteLine("Error! Enter the number correctly!");
removeStr = Console.ReadLine();
}
restaurantManager.RemoveOrder(remove);
}