Which opera  Pelléas et Mélisande and Die schweigsame Frau has fewer acts ?
Pelléas et Mélisande (opera) Pelléas et Mélisande ("Pelléas and Mélisande") is an opera in five acts with music by Claude Debussy. The French libretto was adapted from Maurice Maeterlinck's Symbolist play "Pelléas et Mélisande". It premiered at the Opéra-Comique in Paris on 30 April 1902 with Jean Périer as Pelléas and Mary Garden as Mélisande in a performance conducted by André Messager, who was instrumental in getting the Opéra-Comique to stage the work. The only opera Debussy ever completed, it is considered a landmark in 20th-century music.
Die Frau ohne Schatten Die Frau ohne Schatten (The Woman without a Shadow), Op. 65, is an opera in three acts by Richard Strauss with a libretto by his long-time collaborator, the poet Hugo von Hofmannsthal. It was written between 1911 and either 1915 or 1917. When it premiered in Vienna on 10 October 1919, critics and audiences were unenthusiastic. Many cited problems with Hofmannsthal's complicated and heavily symbolic libretto. However, it is now a standard part of the operatic repertoire.