What is the lowest number of Laps that have a Time of +24.440, and a Grid higher than 18?
CREATE TABLE "125cc_classification" (
  "rider" text,
  "manufacturer" text,
  "laps" real,
  "time" text,
  "grid" real
);
SELECT MIN("laps") FROM "125cc_classification" WHERE "time"='+24.440' AND "grid">18;