Question: A Life for the Tsar is a  Russian libretto with four acts, Tosca an Italian libretto has how many acts?
Sentence (from "Tosca"): The work, based on Victorien Sardou's 1887 French-language dramatic play, "La Tosca", is a melodramatic piece set in Rome in June 1800, with the Kingdom of Naples's control of Rome threatened by Napoleon's invasion of Italy.
Relevant evidence: No