Question: The operas that Helen Donaldson was best known for appearing in were created by a team who collaborated on how many comic operas?

Context articles: Pauline Rita
W. S. Gilbert
William Charles John Pitcher
Marie Jansen
Martyn Green
Helen Donaldson
Robert Reece
Ermanno Wolf-Ferrari
Peter Pratt
Gilbert and Sullivan

Pauline Rita (c.1842 – 28 June 1920) was an English soprano and actress.
 During her early career, she was best known for her performances in operettas and comic operas at the Opera Comique and was associated with impresario Richard D'Oyly Carte.
 Later, she married flautist John Radcliff, and the two performed together for many years.
Sir William Schwenck Gilbert (18 November 1836 – 29 May 1911) was an English dramatist, librettist, poet and illustrator best known for the fourteen comic operas (known as the Savoy operas) produced in collaboration with the composer Sir Arthur Sullivan.
 The most famous of these include "H.M.S. Pinafore", "The Pirates of Penzance" and one of the most frequently performed works in the history of musical theatre, "The Mikado".
 The popularity of these works was supported for over a century by year-round performances of them, in Britain and abroad, by the repertory company that they founded, the D'Oyly Carte Opera Company.
 Eleven of the Savoy operas continue to be frequently performed in the English-speaking world and beyond by opera companies, repertory companies, schools and community theatre groups.
 Lines from these works have become part of the English language, such as "short, sharp shock", "What, never?
 Well, hardly ever!"
, and "Let the punishment fit the crime".
William John Charles Pitcher (21 March 1858 – 2 March 1925), known as Wilhelm or C. Wilhelm, was an English artist, costume and scenery designer, best known for his designs for ballets, pantomimes, comic operas, and Edwardian musical comedies.
Marie Jansen (November 18, 1857 – March 20, 1914) was an American musical theatre actress best known for her roles at the end of the 19th century.
 She starred in a number of successful comic operas, Edwardian musical comedies, and comic plays in New York, Boston, Philadelphia and London during the 1880s and 1890s.
William Martyn-Green (22 April 1899 – 8 February 1975), better known as Martyn Green, was an English actor and singer.
 He is best known for his work as principal comedian in the Gilbert & Sullivan comic operas, which he performed and recorded with the D'Oyly Carte Opera Company and other troupes.
Helen Donaldson (born 14 March 1968 in Rockhampton, Queensland) is an Australian opera singer best known for her performances of the heroines in Gilbert and Sullivan operas.
Robert Reece (2 May 1838 – 8 July 1891) was a British comic playwright and librettist active in the Victorian era.
 He wrote many successful musical burlesques, comic operas, farces and adaptations from the French, including the English-language adaptation of the operetta "Les cloches de Corneville", which became the longest-running piece of musical theatre in history up to that time.
 He sometimes collaborated with Henry Brougham Farnie or others.
Ermanno Wolf-Ferrari (born Ermanno Wolf) (January 12, 1876 – January 21, 1948) was an Italian composer and teacher.
 He is best known for his comic operas such as "Il segreto di Susanna" (1909).
 A number of his works were based on plays by Carlo Goldoni, including "Le donne curiose" (1903), "I quatro rusteghi" (1906) and "Il campiello" (1936).
Peter Pratt (21 March 1923 – 11 January 1995) was an English actor and singer.
 He was best known for his comic roles in the Gilbert and Sullivan comic operas.
Gilbert and Sullivan refers to the Victorian-era theatrical partnership of the librettist W. S. Gilbert (1836–1911) and the composer Arthur Sullivan (1842–1900) and to the works they jointly created.
 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.