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".
Die Schweizer Familie Die Schweizer Familie ("The Swiss Family") is an opera by the Austrian composer Joseph Weigl. It takes the form of a "Singspiel" in three acts. The libretto, by Ignaz Franz Castelli, is based on the vaudeville "Pauvre Jacques" (1807) by Charles-Augustin de Basson-Pierre and René de Chazet. The opera was first performed at the Theater am Kärntnertor in Vienna on 14 March 1809 and was a great success in German-speaking countries in the early 19th century.