Name the total number of moto2 winners for laguna seca
CREATE TABLE "grands_prix" (
  "round" real,
  "date" text,
  "grand_prix" text,
  "circuit" text,
  "moto_gp_winner" text,
  "moto2_winner" text,
  "moto3_winner" text,
  "report" text
);
SELECT COUNT("moto2_winner") FROM "grands_prix" WHERE "circuit"='Laguna Seca';