CREATE TABLE table_73413 ("Season no." FLOAT, "Series no." FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT, "U.S. Viewers  ( millions ) " TEXT)

which is the maximun serie episode number when the millions of North American spectators is 3.14?
SELECT MAX("Series no.") FROM table_73413 WHERE "U.S. Viewers (millions)" = '3.14'
SELECT MAX("Series no.") FROM "table_73413" WHERE "U.S. Viewers (millions)" = '3.14'