What is the number of viewers in millions for the episode on October 10, 2008, and a Channel 4 weekly rank a smaller than 30?
CREATE TABLE "united_kingdom" (
  "episode_num" real,
  "title" text,
  "airdate" text,
  "viewers_millions" real,
  "channel_4_weekly_rank_a" real
);
SELECT COUNT("viewers_millions") FROM "united_kingdom" WHERE "airdate"='october 10, 2008' AND "channel_4_weekly_rank_a"<30;