How many timeslots were available for the season finale on August 29, 2009?
CREATE TABLE "seasonal_ratings" (
  "season" real,
  "episodes" real,
  "timeslot_et" text,
  "season_premiere" text,
  "season_finale" text,
  "tv_season" text,
  "rank" text,
  "viewers_in_millions" text
);
SELECT COUNT("timeslot_et") FROM "seasonal_ratings" WHERE "season_finale"='August 29, 2009';