Question: The operas that Helen Donaldson was best known for appearing in were created by a team who collaborated on how many comic operas?
Sentence (from "Gilbert and Sullivan"): The two men collaborated on fourteen comic operas between 1871 and 1896, of which "H.M.S. Pinafore", "The Pirates of Penzance" and "The Mikado" are among the best known.
Relevant evidence: Yes