Question: Which opera has more acts, Der Zwerg or Billy Budd?
{'answer': 'Billy Budd, Op. 50, is an opera by Benjamin Britten to a libretto by the English novelist E. M. Forster and Eric Crozier, based on the short novel "Billy Budd" by Herman Melville. Originally in four acts, it was first performed at the Royal Opera House, London, on 1 December 1951; it was later revised as a two-act opera with a prologue and an epilogue.', 'supporting_facts': [['Der Zwerg', 1], ['Billy Budd (opera)', 1]]}