What is the season number of the show written by both Kari Lizer and Jeff Astrof?
CREATE TABLE "table1_27911342_1" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "written_by" text,
  "original_air_date" text,
  "u_s_viewers_millions" text
);
SELECT COUNT("season_num") FROM "table1_27911342_1" WHERE "written_by"='Kari Lizer';