Does Werther or War and Peace have more acts?
Werther Werther is an opera ("drame lyrique") in four acts by Jules Massenet to a French libretto by Édouard Blau, Paul Milliet and Georges Hartmann (who used the pseudonym Henri Grémont). It is loosely based on the German epistolary novel "The Sorrows of Young Werther" by Johann Wolfgang von Goethe, which was based both on fact and on Goethe's own early life. Earlier examples of operas using the story were made by Kreutzer (1792) and Pucitta (1802).
I puritani I puritani ("The Puritans") is an opera in by Vincenzo Bellini. It was originally written in two acts and later changed to three acts on the advice of Gioachino Rossini, with whom the young composer had become friends. The music was set to a libretto by Count Carlo Pepoli, an Italian émigré poet whom Bellini had met at a salon run by the exile Princess Belgiojoso, which became a meeting place for many Italian revolutionaries.