A Life for the Tsar is a  Russian libretto with four acts, Tosca an Italian libretto has how many acts?
Tosca Tosca (] ) is an opera in three acts by Giacomo Puccini to an Italian libretto by Luigi Illica and Giuseppe Giacosa. It premiered at the Teatro Costanzi in Rome on 14 January 1900. 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. It contains depictions of torture, murder and suicide, as well as some of Puccini's best-known lyrical arias.
Genoveva Genoveva, Op. 81, is an opera in four acts by Robert Schumann in the genre of German Romanticism with a libretto by Robert Reinick and the composer. The only opera Schumann ever wrote, it received its first performance on 25 June 1850 at the Stadttheater in Leipzig, with the composer conducting. It received only three performances during the premiere, and the negative criticism it received in the press played a decisive role in Schumann's decision to not write a second opera.