What is the sum of gold medals for the United States with silver medal count greater than 3?
CREATE TABLE "medal_count" (
  "rank" real,
  "nation" text,
  "gold" real,
  "silver" real,
  "bronze" real,
  "total" real
);
SELECT SUM("gold") FROM "medal_count" WHERE "nation"='united states' AND "silver">3;