text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE table_name_68 (quantity_preserved VARCHAR, manufacturer VARCHAR, class VARCHAR)
  ### Question:
  How many did alco -schenectady preserve of class b-3?
  ### Answer:
  SELECT quantity_preserved FROM table_name_68 WHERE manufacturer = "alco -schenectady" AND class = "b-3"