How many people were in attendance when the visiting team was the Nuggets and the leading scorer was J.R. Smith (28)?
CREATE TABLE "february" (
  "date" text,
  "visitor" text,
  "score" text,
  "home" text,
  "leading_scorer" text,
  "attendance" real,
  "record" text
);
SELECT SUM("attendance") FROM "february" WHERE "visitor"='nuggets' AND "leading_scorer"='j.r. smith (28)';