what is the total viewers (m) when the rating is 6.4 and the share is more than 11?
CREATE TABLE "weekly_ratings" (
  "episode" text,
  "air_date" text,
  "rating" real,
  "share" real,
  "18_49_rating_share" text,
  "viewers_m" real,
  "rank_timeslot" text
);
SELECT COUNT("viewers_m") FROM "weekly_ratings" WHERE "rating"=6.4 AND "share">11;