How many wins have a year after 1976, and 350cc as the class?
CREATE TABLE "grand_prix_motorcycle_racing_results" (
  "year" real,
  "class" text,
  "team" text,
  "points" real,
  "wins" real
);
SELECT SUM("wins") FROM "grand_prix_motorcycle_racing_results" WHERE "year">1976 AND "class"='350cc';