Question: When did Ukraine gain independence from the country of citizenship of the director of Faust?

full_context: Document 1: The Degraded: The Degraded () is the second film by Alexander Sokurov. It was released in 1980 and is of 30 minutes duration.
Document 2: The Second Circle: The Second Circle () is a 1990 Soviet Union drama film directed by Aleksandr Sokurov that tells the story of a young man who tries to deal with his father's death and the difficulties of his burial in a worldly society.
Document 3: Ukraine: German armies invaded the Soviet Union on 22 June 1941, initiating nearly four years of total war. The Axis initially advanced against desperate but unsuccessful efforts of the Red Army. In the encirclement battle of Kiev, the city was acclaimed as a "Hero City", because of its fierce resistance. More than 600,000 Soviet soldiers (or one-quarter of the Soviet Western Front) were killed or taken captive there, with many suffering severe mistreatment.Although the majority of Ukrainians fought in or alongside the Red Army and Soviet resistance, in Western Ukraine an independent Ukrainian Insurgent Army movement arose (UPA, 1942). Created as armed forces of the underground (Organization of Ukrainian Nationalists, OUN) which had developed in interwar Poland as a reactionary nationalist organization. During the interwar period, the Polish government's policies towards the Ukrainian minority were initially very accommodating, however by the late 1930s they became increasingly harsh due to civil unrest. Both organizations, OUN and UPA supported the goal of an independent Ukrainian state on the territory with a Ukrainian ethnic majority. Although this brought conflict with Nazi Germany, at times the Melnyk wing of the OUN allied with the Nazi forces. Also, UPA divisions carried out massacres of ethnic Poles, which brought reprisals. After the war, the UPA continued to fight the USSR until the 1950s. At the same time, the Ukrainian Liberation Army, another nationalist movement, fought alongside the Nazis.
Document 4: Ruslan and Ludmila: Ruslan and Ludmila (pre-reform Russian: ; post-reform ) is a poem by Alexander Pushkin, published in 1820. It is written as an epic fairy tale consisting of a dedication (посвящение), six "cantos" (), and an epilogue (). It tells the story of the abduction of Ludmila, the daughter of Prince Vladimir of the Kievan Rus' (reigned 980–1015), by an evil wizard and the attempt by the brave knight Ruslan to find and rescue her.
Document 5: Moscow Elegy: Moscow Elegy () is a 1988 documentary film directed by Alexander Sokurov, about the later life and death of Soviet Russian filmmaker Andrei Tarkovsky. The film was originally intended to mark the 50th birthday of Tarkovsky in 1982, which would have been before his death. Controversy with Soviet authorities about the film's style and content led to significant delays in the production.
Document 6: Faust (2011 film): Faust is a 2011 Russian film directed by Alexander Sokurov. Set in the 19th century, it is a free interpretation of the Faust legend and its respective literary adaptations by both Johann Wolfgang von Goethe as well as Thomas Mann. The dialogue is in German. The film won the Golden Lion at the 68th Venice International Film Festival. At the 2012 Russian Guild of Film Critics Awards the film was awarded the prizes for Best Film, Best Director (Alexander Sokurov), Best Script (Yuri Arabov) and Best Male Supporting Actor (Anton Adasinsky).
Document 7: Trial on the Road: "Trial on the Road" was censored and taken out of circulation in the Soviet Union for 15 years after its release due to its controversial depiction of Soviet soldiers. The film is based on a story by the director's father, Yuri German. The screenplay was written by Eduard Volodarsky.
Document 8: Bukovina: A region of Moldavia during the Middle Ages, the territory of what became known as Bukovina was, from 1774 to 1918, an administrative division of the Habsburg Monarchy, the Austrian Empire, and Austria-Hungary. After World War I, Romania established its control over Bukovina. In 1940, the northern half of Bukovina was annexed by the Soviet Union in violation of the Molotov–Ribbentrop Pact, and currently is part of Ukraine.
Document 9: Symon Petliura: (Ukrainian: Си́мон Васи́льович Петлю́ра; May 10, 1879 – May 25, 1926) was a Ukrainian politician and journalist. He became the Supreme Commander of the Ukrainian Army and the President of the Ukrainian People's Republic during Ukraine's short-lived sovereignty in 1918–1921, leading Ukraine's struggle for independence following the fall of the Russian Empire in 1917.
Document 10: Khosrow Mirza: A young Khosrow Mirza is briefly depicted in Alexander Sokurov's 2002 film Russian Ark. The film also portrays Khosrow's elaborate ceremonial apology before the Russian Tsar.
Document 11: The Laboratory of Mephistopheles: The Laboratory of Mephistopheles (), initially released in Britain and America as Laboratory of Mephistopheles and also known as The Cabinet of Mephistopheles, The Devil's Laboratory, Faust's Laboratory, and The Laboratory of Faust, was an 1897 short silent film directed by Georges Méliès, loosely inspired by the Faust legend.
Document 12: Crimean People's Republic: The Crimean People's Republic () () existed from December 1917 to January 1918 in the Crimean Peninsula, a territory currently disputed between the Russian Federation and Ukraine. Crimean People’s Republic was the first Turkic and Muslim democratic republic in the world. In its founding, the Crimean People's Republic was one of many short-lived attempts to create new states after the Russian Revolution of 1917 had caused the Russian Empire to collapse.
Document 13: Fabian (film): Fabian is a 1980 West German drama film directed by Wolf Gremm. It is based on the novel "Fabian, the Story of a Moralist" (1931) by German author Erich Kästner. The film was chosen as West Germany's official submission to the 53rd Academy Awards for Best Foreign Language Film, but did not manage to receive a nomination.
Document 14: Faun (film): Faun is a 1918 Hungarian silent drama film directed by Alexander Korda and starring Gábor Rajnay, Dezsõ Gyárfás and Artúr Somlay. It was based on a play by Edward Knoblock.
Document 15: History of Ukraine: Between 1917 and 1920, several entities that aspired to be independent Ukrainian states came into existence. This period, however, was extremely chaotic, characterized by revolution, international and civil war, and lack of strong central authority. Many factions competed for power in the area that is today's Ukraine, and not all groups desired a separate Ukrainian state. Ultimately, Ukrainian independence was short - lived, as most Ukrainian lands were incorporated into the Soviet Union and the remainder, in western Ukraine, was divided among Poland, Czechoslovakia, and Romania.
ground_truth: 1917
sub_queries: Faust >> director Answer: Alexander Sokurov
Alexander Sokurov >> country of citizenship Answer: Soviet Union
when did ukraine gain independence from Soviet Union Answer: 1917