Which Capacity has a Class of cm22, and a Vehicle of 1999 subaru impreza wrx sti?
CREATE TABLE "rookie_rallye_modern_competition" (
  "driver" text,
  "navigator" text,
  "vehicle" text,
  "class" text,
  "capacity" real,
  "total_time" text,
  "margin" text
);
SELECT MIN("capacity") FROM "rookie_rallye_modern_competition" WHERE "class"='cm22' AND "vehicle"='1999 subaru impreza wrx sti';