CREATE TABLE table_74227 ("Series no." FLOAT, "Season no." FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT, "U.S. viewers  ( millions ) " TEXT)

at most what number in the series was the episode 'chet episode'?
SELECT MAX("Series no.") FROM table_74227 WHERE "Title" = 'Chet Episode'
SELECT MAX("Series no.") FROM "table_74227" WHERE "Title" = 'Chet Episode'