What country were the athletes where ranked smaller than 5 with notes listed as fb?
CREATE TABLE "semifinal_a_b_2" (
  "rank" real,
  "rowers" text,
  "country" text,
  "time" text,
  "notes" text
);
SELECT "country" FROM "semifinal_a_b_2" WHERE "rank"<5 AND "notes"='fb';