Which opera  Pelléas et Mélisande and Die schweigsame Frau has fewer acts ?
Die schweigsame Frau Die schweigsame Frau ("The Silent Woman"), Op. 80, is a 1935 opera in three acts by Richard Strauss with libretto by Stefan Zweig after Ben Jonson's "Epicoene, or the Silent Woman".
Bluebeard (ballet) Barbe-bleue (en. "Bluebeard") (ru. «Синяя борода», "Sinjaja boroda") is a "ballet-féerie" in three acts and seven scenes, originally choreographed by Marius Petipa to the music of Pyotr Schenk. The libretto was created by the author and dramatist Countess Lydia Pashkova from the fairy tale "Bluebeard" by Charles Perrault. The ballet was first presented by the Imperial Ballet on December 20 [O.S. December 8] 1896 at the Imperial Mariinsky Theatre in St. Petersburg, Russia, the first performance being a benefit in honor of Marius Petipa's fiftieth anniversary in service to the St. Petersburg Imperial Theatres.