What is the season number of the episode directed by Donald Crombie and the series number is 40?
CREATE TABLE "table1_16175064_3" (
  "season_num" real,
  "series_num" real,
  "title" text,
  "director_s" text,
  "writer_s" text,
  "original_airdate" text
);
SELECT "season_num" FROM "table1_16175064_3" WHERE "director_s"='Donald Crombie' AND "series_num"=40;