What is the total number sunk by warship or raider with 20 German submarines lost and more than 21616 sunk by aircraft?
CREATE TABLE "references" (
  "month_year" text,
  "sunk_by_u_boat" real,
  "sunk_by_aircraft" real,
  "sunk_by_warship_or_raider" real,
  "sunk_by_mines" real,
  "german_submarines_lost" real
);
SELECT COUNT("sunk_by_warship_or_raider") FROM "references" WHERE "german_submarines_lost"=20 AND "sunk_by_aircraft">21616;