Question: Leoš Janáček and Sergei Prokofiev are both what?

full_context: Document 1: Janáček (crater): Janáček is a crater on Mercury. It has a diameter of 47 kilometers. Its name was adopted by the International Astronomical Union in 1985. Janáček is named for the Czech composer Leoš Janáček, who lived from 1854 to 1928.
Document 2: Violin Sonata (Janáček): Violin Sonata, a composition for violin and piano, is a work of the Czech composer Leoš Janáček (1854-1928). It was written in the summer of 1914, but it was not Janáček’s first attempt to create such a composition. He resolved to compose a violin sonata already as a student at the conservatoire in Leipzig in 1880, and later during his studies in Vienna. His early sonatas are today lost.
Document 3: Piano Sonata No. 9 (Prokofiev): Sergei Prokofiev's Piano Sonata No. 9 in C major, Op. 103 (1947) is a sonata for solo piano composed in 1947 and consists of four movements. The sonata was dedicated to Sviatoslav Richter, a member of the Union of Soviet Composers, and by whom it was first performed on 21 April 1951 in Moscow.
Document 4: Sergei Prokofiev: Sergei Sergeyevich Prokofiev ( ; Russian: Сергей Сергеевич Прокофьев , "Sergej Sergejevič Prokofjev" ; 27 April 1891 – 5 March 1953) was a Soviet composer, pianist and conductor. As the creator of acknowledged masterpieces across numerous musical genres, he is regarded as one of the major composers of the 20th century. His works include such widely heard works as the March from "The Love for Three Oranges," the suite "Lieutenant Kijé", the ballet "Romeo and Juliet" – from which "Dance of the Knights" is taken – and "Peter and the Wolf." Of the established forms and genres in which he worked, he created – excluding juvenilia – seven completed operas, seven symphonies, eight ballets, five piano concertos, two violin concertos, a cello concerto, a Symphony-Concerto for cello and orchestra, and nine completed piano sonatas.
Document 5: Piano Concerto No. 5 (Prokofiev): The last complete piano concerto by Sergei Prokofiev, Piano Concerto No. 5 in G major, Op. 55, dates from 1932.
Document 6: Sinfonietta (Janáček): The Sinfonietta (subtitled “Military Sinfonietta” or “Sokol Festival”) is a very expressive and festive, late work for large orchestra (of which 25 are brass players) by the Czech composer Leoš Janáček. It is dedicated “To the Czechoslovak Army” and Janáček said it was intended to express “contemporary free man, his spiritual beauty and joy, his strength, courage and determination to fight for victory.” It started by Janáček listening to a brass band, becoming inspired to write some fanfares of his own. When the organisers of the Sokol Gymnastic Festival approached him for a commission, he developed the material into the "Sinfonietta". He later dropped the word "military". The first performance was in Prague on 26 June 1926 under Václav Talich. Typical performance duration is 20–25 minutes.
Document 7: Sergei Rachmaninoff: Sergei Vasilievich Rachmaninoff (Russian: Серге́й Васи́льевич Рахма́нинов , "Sergey Vasilyevich Rakhmaninov"; ] ; 1 April [O.S. 20 March] 1873 28 March 1943) was a Russian virtuoso pianist, composer, and conductor of the late-Romantic period, some of whose works are among the most popular in the romantic repertoire.
Document 8: Leoš Janáček International Competition in Brno: The Leoš Janáček International Competition in Brno (hereinafter referred to as MSLJ) (Czech: Mezinárodní soutěž Leoše Janáčka v Brně ) is a music competition held annually by the Faculty of Music of the Janáček Academy of Music and Performing Arts Brno. The MSLJ was named after the famous composer Leoš Janáček.
Document 9: Leoš Janáček: Leoš Janáček (] , baptised Leo Eugen Janáček; 3 July 1854 – 12 August 1928) was a Czech composer, musical theorist, folklorist, publicist and teacher. He was inspired by Moravian and other Slavic folk music to create an original, modern musical style.
Document 10: Violin Sonata No. 1 (Prokofiev): Sergei Prokofiev's Violin Sonata No. 1 in F minor, Op 80, written between 1938 and 1946 (completed two years after Violin Sonata No. 2), is one of the darkest and most brooding of the composer's works.
Document 11: Piano Sonata No. 7 (Prokofiev): Sergei Prokofiev's Piano Sonata No. 7 in B♭ major, Op. 83 (1942) (occasionally called the "Stalingrad") is a sonata composed for solo piano, the second of the three "War Sonatas". The sonata was first performed on 18 January 1943 in Moscow by Sviatoslav Richter.
Document 12: Antonín Dvořák: Antonín Leopold Dvořák ( ; ] ; 8 September 1841 – 1 May 1904) was a Czech composer. After Bedřich Smetana, he was the second Czech composer to achieve worldwide recognition. Following Smetana's nationalist example, Dvořák frequently employed aspects, specifically rhythms, of the folk music of Moravia and his native Bohemia. Dvořák's own style has been described as "the fullest recreation of a national idiom with that of the symphonic tradition, absorbing folk influences and finding effective ways of using them."
Document 13: Violin Concerto No. 1 (Prokofiev): Sergei Prokofiev began his Violin Concerto No. 1 in D major, opus 19, as a concertino in 1915 but soon abandoned it to work on his opera "The Gambler". He returned to the concerto in the summer of 1917. It premiered on October 18, 1923 at the Paris Opera with Marcel Darrieux playing the violin part and the Paris Opera Orchestra conducted by Serge Koussevitzky. Igor Stravinsky made his debut as conductor at the same concert, conducting the first performance of his own Octet for Wind Instruments.
Document 14: Leoš Firkušný: Leoš Firkušný was a Czech musicologist. He was born on July 16, 1905 in Napajedla (today's Czech Republic). He was an older brother of the famous pianist Rudolf Firkušný. He was an expert on Leoš Janáček and did much to bring his music to the listeners abroad. He was one of the founders of the music festival Prague Spring. He died on July 9, 1950 in Buenos Aires, Argentina.
Document 15: Dmitri Shostakovich: Dmitri Dmitriyevich Shostakovich (Russian: Dmitriy Dmitrievich Shostakovich , ] ; 25 September [O.S. 12 September] 1906 9 August 1975) was a Russian composer and pianist. He is regarded as one of the major composers of the 20th century.
ground_truth: composer