What is the average medal total of the country who had 0 silver medals and participated in less than 15 games?
CREATE TABLE "participation_and_medals" (
  "games" real,
  "first" real,
  "last" real,
  "gold" real,
  "silver" real,
  "bronze" real,
  "total" real,
  "best_finish_first_last" text
);
SELECT AVG("total") FROM "participation_and_medals" WHERE "games"<15 AND "silver"<0;