How many times did the episode "team impossible" originally air?
CREATE TABLE "table1_2623498_4" (
  "episode_num" text,
  "season_episode_num" text,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "prod_code" text
);
SELECT COUNT("original_air_date") FROM "table1_2623498_4" WHERE "title"='\"Team Impossible\"';