How many locations are listed for the Big 12 Conference?
CREATE TABLE "table1_22645714_5" (
  "conference" text,
  "regular_season_winner" text,
  "conference_player_of_the_year" text,
  "conference_tournament" text,
  "tournament_venue_city" text,
  "tournament_winner" text
);
SELECT COUNT("tournament_venue_city") FROM "table1_22645714_5" WHERE "conference"='Big 12 Conference';