Question: When did East Germany unite with the country Boney M. came from?

full_context: Document 1: Berlin Wall: In 1989 a series of revolutions in nearby Eastern Bloc countries -- Poland and Hungary in particular -- caused a chain reaction in East Germany that ultimately resulted in the demise of the Wall. After several weeks of civil unrest, the East German government announced on 9 November 1989 that all GDR citizens could visit West Germany and West Berlin. Crowds of East Germans crossed and climbed onto the Wall, joined by West Germans on the other side in a celebratory atmosphere. Over the next few weeks, euphoric people and souvenir hunters chipped away parts of the Wall; the governments later used industrial equipment to remove most of what was left. The ``fall of the Berlin Wall ''paved the way for German reunification, which formally took place on 3 October 1990.
Document 2: Bee Gees: When it, too, failed to attract much interest, Mardin encouraged them to work within the soul music style. The brothers attempted to assemble a live stage band that could replicate their studio sound. Lead guitarist Alan Kendall had come on board in 1971 but did not have much to do until Mr. Natural. For that album, they added drummer Dennis Bryon, and they later added ex-Strawbs keyboard player Blue Weaver, completing the Bee Gees band that lasted through the late '70s. Maurice, who had previously performed on piano, guitar, harpsichord, electric piano, organ, mellotron and bass guitar, as well as mandolin and Moog synthesiser, by then confined himself to bass onstage.
Document 3: Boney M.: Boney M. was a German vocal group created by German record producer Frank Farian. Originally based in West Germany, the four original members of the group's official line - up were Liz Mitchell and Marcia Barrett from Jamaica, Maizie Williams from Montserrat and Bobby Farrell from Aruba. The group was formed in 1976 and achieved popularity during the disco era of the late 1970s. Since the 1980s, various line - ups of the band have performed with different personnel.
Document 4: Germany: After Germany surrendered, the Allies partitioned Berlin and Germany's remaining territory into four military occupation zones. The western sectors, controlled by France, the United Kingdom, and the United States, were merged on 23 May 1949 to form the Federal Republic of Germany (Bundesrepublik Deutschland); on 7 October 1949, the Soviet Zone became the German Democratic Republic (Deutsche Demokratische Republik). They were informally known as West Germany and East Germany. East Germany selected East Berlin as its capital, while West Germany chose Bonn as a provisional capital, to emphasize its stance that the two - state solution was an artificial and temporary status quo.
Document 5: Bee Gees: The Bee Gees were a pop music group formed in 1958. Their lineup consisted of brothers Barry, Robin, and Maurice Gibb. The trio were successful for most of their decades of recording music, but they had two distinct periods of exceptional success: as a popular music act in the late 1960s and early 1970s, and as prominent performers of the disco music era in the mid-to - late 1970s. The group sang recognisable three - part tight harmonies; Robin's clear vibrato lead vocals were a hallmark of their earlier hits, while Barry's R&B falsetto became their signature sound during the mid-to - late 1970s and 1980s. The Bee Gees wrote all of their own hits, as well as writing and producing several major hits for other artists.
Document 6: Unification of Germany: The unification of Germany into a politically and administratively integrated nation state officially occurred on 18 January 1871, in the Hall of Mirrors at the Palace of Versailles in France. Princes of the German states, excluding Austria, gathered there to proclaim Wilhelm I of Prussia as German Emperor after the French capitulation in the Franco - Prussian War. Unofficially, the de facto transition of most of the German - speaking populations into a federated organization of states had been developing for some time through alliances formal and informal between princely rulers -- but in fits and starts; self - interests of the various parties hampered the process over nearly a century of autocratic experimentation, beginning in the era of the Napoleonic Wars, which saw the dissolution of the Holy Roman Empire of the German Nation (1806), and the subsequent rise of German nationalism.
Document 7: Bee Gees: At Eric Clapton's suggestion, the brothers moved to Miami, Florida, early in 1975 to record. After starting off with ballads, they eventually heeded the urging of Mardin and Stigwood, and crafted more dance-oriented disco songs, including their second US No. 1, "Jive Talkin'", along with US No. 7 "Nights on Broadway". The band liked the resulting new sound. This time the public agreed by sending the LP Main Course up the charts. This album included the first Bee Gees songs wherein Barry used falsetto, something that would later become a trademark of the band. This was also the first Bee Gees album to have two US top-10 singles since 1968's Idea. Main Course also became their first charting R&B album.
Document 8: German reunification: The German reunification (German: Deutsche Wiedervereinigung) was the process in 1990 in which the German Democratic Republic (GDR / DDR / East Germany) joined the Federal Republic of Germany (FRG / West Germany) to form the reunited nation of Germany, and when Berlin reunited into a single city, as provided by its then Grundgesetz constitution Article 23. The end of the unification process is officially referred to as German unity (German: Deutsche Einheit), celebrated on 3 October (German Unity Day) (German: Tag der deutschen Einheit). Following German reunification, Berlin was once again designated as the capital of united Germany.
Document 9: History of Germany (1945–1990): The intended governing body of Germany was called the Allied Control Council. The commanders - in - chief exercised supreme authority in their respective zones and acted in concert on questions affecting the whole country. Berlin, which lay in the Soviet (eastern) sector, was also divided into four sectors with the Western sectors later becoming West Berlin and the Soviet sector becoming East Berlin, capital of East Germany.
Document 10: Children of Paradise (song): "Children of Paradise" / "Gadda-Da-Vida" is a 1980 single by German band Boney M. Intended to be the first single from the group's fifth album "Boonoonoonoos" (originally scheduled for a November 1980 release), the single was ultimately never included because the album release was delayed for one year. "Children of Paradise" peaked at #11 in the German charts whereas it became the group's lowest placing in the UK at #66 only when released in February '81. Boney M. would use the double A-side format in this period, typically with the A1 being the song intended for radio and A2 being more squarely aimed at discos. The sides would usually be switched on the accompanying 12" single.
Document 11: Everybody Wants to Dance Like Josephine Baker: "Everybody Wants to Dance Like Josephine Baker" is a 1989 single by German band Boney M. Produced by Barry Blue and recorded by original Boney M. members Marcia Barrett, Bobby Farrell, Maizie Williams and singer Madeleine Davis replacing Liz Mitchell, the single was withdrawn when original producer Frank Farian claimed copyright to the name Boney M. and a court case followed. In France, the single was released credited to "Bobby Marcia Maizie Matalyne". To benefit from the fuss that was stirred by the record, Farian rushed out the single "Stories" with a competitive line-up featuring original lead singer Liz Mitchell, Reggie Tsiboe (who replaced Farrell in the group from 1982–86) and two new girls.
Document 12: Young, Free and Single: "Young, Free and Single" is a single by German band Boney M., taken from their final album "Eye Dance" (1985). Only a modest hit, the single peaked at #49 in the German charts. Being a novelty record, the lyrics were about a radio talkshow for dating. Male dancer Bobby Farrell was featured in heavily disguised vocoder vocals in the verses while Reggie Tsiboe did the lead vocals on the chorus. The B-side "Blue Beach" was an instrumental dub version.
Document 13: Territorial evolution of Germany: The territorial changes of Germany include all changes in the borders and territory of Germany from its formation in 1871 to the present. Modern Germany was formed in 1871 when Otto von Bismarck unified most of the German states, with the notable exception of Austria, into the German Empire. After the First World War, Germany lost about 10% of its territory to its neighbours and the Weimar Republic was formed. This republic included territories to the east of today's German borders.
Document 14: Belfast (Boney M. song): "Belfast" is the second single of the Euro disco band Boney M.'s 1977 album "Love for Sale". "Belfast" was the first Boney M. single to feature lead vocals by Marcia Barrett and became their 4th consecutive German chart-topper. In the UK Singles Chart it peaked at No. 8. It remained a popular track in the group's live shows over the years and was re-recorded by Marcia Barrett as a solo track on her album "Come Into My Life" (2005).
Document 15: Dresden: Since German reunification in 1990 Dresden is again a cultural, educational and political centre of Germany and Europe. The Dresden University of Technology is one of the 10 largest universities in Germany and part of the German Universities Excellence Initiative. The economy of Dresden and its agglomeration is one of the most dynamic in Germany and ranks first in Saxony.  It is dominated by high-tech branches, often called “Silicon Saxony”. The city is also one of the most visited in Germany with 4.3 million overnight stays per year. The royal buildings are among the most impressive buildings in Europe. Main sights are also the nearby National Park of Saxon Switzerland, the Ore Mountains and the countryside around Elbe Valley and Moritzburg Castle. The most prominent building in the city of Dresden is the Frauenkirche. Built in the 18th century, the church was destroyed during World War II. The remaining ruins were left for 50 years as a war memorial, before being rebuilt between 1994 and 2005.
ground_truth: 1990
sub_queries: where does the group boney m come from Answer: West Germany
when did east germany and West Germany unite Answer: 1990