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.
Marie Wilt Marie Wilt (also Maria Vilda and Marie Liebenthaler) (30 January 1833 – 24 September 1891) was an Austrian dramatic coloratura soprano. Possessing a wide vocal range with a significant amount of power and flexibility, Wilt sang a wide repertoire that encompassed the operas of Wolfgang Amadeus Mozart, the German operas of Richard Wagner, the grand operas of Giuseppe Verdi, and the bel canto operas of Bellini, Rossini, and Donizetti. She sang for many years at the Vienna Hofoper (now Vienna State Opera) and for a number of seasons at the Royal Opera House, Covent Garden in London. She notably portrayed the role of Sulamith in the world premiere of Karl Goldmark's "Die Königin von Saba" in 1875. Also a regular performer of the concert repertoire, Wilt often appeared in performances of works by Beethoven, Haydn, and Mendelssohn.