CREATE TABLE table_204_939 (id DECIMAL, "year" DECIMAL, "chassis" TEXT, "engine" TEXT, "start" TEXT, "finish" TEXT)

how many engines were not cosworth 's ?
SELECT COUNT("engine") FROM table_204_939 WHERE "engine" <> 'cosworth'
SELECT COUNT("engine") FROM "table_204_939" WHERE "engine" <> 'cosworth'