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".
Don Quichotte Don Quichotte ("Don Quixote") is an opera in five acts by Jules Massenet to a French libretto by Henri Caïn. It was first performed on 19 February 1910 at the Opéra de Monte-Carlo.