Name the sum of year for connaught engineering and points less than 0
CREATE TABLE "complete_world_championship_formula_one_" (
  "year" real,
  "entrant" text,
  "chassis" text,
  "engine" text,
  "points" real
);
SELECT SUM("year") FROM "complete_world_championship_formula_one_" WHERE "entrant"='connaught engineering' AND "points"<0;