How many heavy attacks did the 450 Luftflotte 2 conduct?
CREATE TABLE "the_blitz_estimated_luftwaffe_sorties" (
  "month_year" text,
  "day_sorties_losses" text,
  "night_sorties_losses" text,
  "luftflotte_2_sorties" real,
  "luftflotte_3_sorties" real,
  "major_attacks" text,
  "heavy_attacks" real
);
SELECT COUNT("heavy_attacks") FROM "the_blitz_estimated_luftwaffe_sorties" WHERE "luftflotte_2_sorties"=450;