Question: Who is the father of the cast member in The Wall - Live in the birthplace of Botho Graef?

full_context: Document 1: Michael John Fles: Michael John Fles was born to a Dutch father, George Fles, and a British mother, Pearl Rimel. As conscious communists, his parents had moved to the Soviet Union, where his father fell victim to Joseph Stalin's Great Purge. The mother, pregnant with Michael John, left the Soviet Union to give birth in London. Mother and son later emigrated to the United States, where Pearl Rimel found employment in the aircraft industry. Michael John grew up in Los Angeles and Ojai, California, where he graduated from the Ojai Valley School in 1950.
Document 2: Judah Waten: Born in Odessa to a Russian-Jewish family, Judah Waten arrived in Western Australia in 1914. He attended Christian Brothers' College, Perth and, moving to Melbourne in 1926, University High School, Melbourne. He joined the Communist Party of Australia while still at school. Between 1931 and 1933, he visited Europe, became engaged in left-wing political activities in England, and spent three months in Wormwood Scrubs Prison.
Document 3: Luther W. Graef: Luther W. Graef is the founder of Graef, Anhalt, Schloemer and Associates Inc., former President of American Society of Civil Engineers (ASCE) and the fourth president of ASCE Foundation.
Document 4: Botho Graef: Franz Botho Graef (12 October 1857, Berlin – 9 April 1917, Königstein im Taunus) was a German classical archaeologist and art historian. His father was painter Gustav Graef, and his sister, Sabine Lepsius, was also an artist of some note. Graef taught at the University of Jena from 1904 until 1917.
Document 5: Arnold Genthe: Arnold Genthe was born in Berlin, Prussia, to Luise Zober and Hermann Genthe, a professor of Latin and Greek at the Graues Kloster (Grey Monastery) in Berlin. Genthe followed in his father's footsteps, becoming a classically trained scholar; he received a doctorate in philology in 1894 from the University of Jena, where he knew artist Adolf Menzel, his mother's cousin.
Document 6: 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 7: Berlin Wall: The Berlin Wall (German: Berliner Mauer) was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989. Constructed by the German Democratic Republic (GDR, East Germany), starting on 13 August 1961, the Wall completely cut off (by land) West Berlin from surrounding East Germany and from East Berlin until government officials opened it in November 1989. Its demolition officially began on 13 June 1990 and finished in 1992. The barrier included guard towers placed along large concrete walls, accompanied by a wide area (later known as the ``death strip '') that contained anti-vehicle trenches,`` fakir beds'' and other defenses. The Eastern Bloc portrayed the Wall as protecting its population from fascist elements conspiring to prevent the ``will of the people ''in building a socialist state in East Germany. In practice, the Wall served to prevent the massive emigration and defection that had marked East Germany and the communist Eastern Bloc during the post-World War II period.
Document 8: Scorpions (band): On the Savage Amusement tour in 1988, the Scorpions became only the second Western group (not American) to play in the Soviet Union. Uriah Heep had performed in December 1987 in Leningrad. The following year the band returned to perform at the Moscow Music Peace Festival. As a result, the Scorpions developed an extended Russian fan base and still return to perform. Also in 1989, Scorpions released the compilation album Best of Rockers 'n' Ballads, which, in addition to the band's hits from 1979 to 1988, included several rare or previously unreleased tracks: "Hey You", from the Animal Magnetism sessions; the re-recorded "long version" of "Is There Anybody There?"; and a cover of The Who's "I Can't Explain", which was also included on that same year's Stairway to Heaven/Highway to Hell charity compilation album. This is the Scorpions' only compilation album to be certified platinum in the United States.Wishing to distance themselves from the Savage Amusement style, the band separated from their long-time producer and "Sixth Scorpion", Dieter Dierks, replacing him with Keith Olsen when they returned to the studio in 1990. Crazy World was released that year and displayed a less polished sound. The album was propelled in large part by the massive success of the ballad "Wind of Change". The song muses on the socio-political changes that were occurring in Eastern Europe and other parts of the world at the end of the Cold War. Crazy World is the band's last album to receive gold or platinum certification in the United States. On 21 July 1990 they joined many other guests for Roger Waters' massive performance of The Wall in Berlin. Scorpions performed both versions of "In the Flesh" from The Wall.
Document 9: Berlin Wall: The Berlin Wall (German: Berliner Mauer, pronounced (bɛʁˈliːnɐ ˈmaʊ̯ɐ) (listen)) was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989. Constructed by the German Democratic Republic (GDR, East Germany), starting on 13 August 1961, the Wall cut off (by land) West Berlin from virtually all of surrounding East Germany and East Berlin until government officials opened it in November 1989. Its demolition officially began on 13 June 1990 and finished in 1992. The barrier included guard towers placed along large concrete walls, accompanied by a wide area (later known as the ``death strip '') that contained anti-vehicle trenches,`` fakir beds'' and other defenses. The Eastern Bloc portrayed the Wall as protecting its population from fascist elements conspiring to prevent the ``will of the people ''in building a socialist state in East Germany.
Document 10: Franz Grashof: Born in Duesseldorf, Germany, as the son of Elisabeth Brüggemann and Karl Grashof, who taught at an upper secondary school, Franz Grashof visited the elementary and lower secondary school in Duesseldorf and the industrial school in Hagen.
Document 11: Roger Waters discography: Roger Waterss primary instrument is the electric bass guitar. He briefly played a Höfner bass but replaced it with a Rickenbacker RM-1999/4001S, until around 1970 when he switched to Fender Precision basses. He often plays bass using a pick but is also known to play fingerstyle. Not only a bassist and vocalist, Waters has experimented with the EMS Synthi A and VCS 3 synthesisers and has played electric rhythm and acoustic guitars in recordings and in concert. Throughout his career he has used Selmer, WEM, Hiwatt and Ashdown amplifiers, also employing delay, tremolo, chorus, panning and phaser effects in his music.
Document 12: Roger Waters: Waters was born on 6 September 1943, the younger of two boys, to Mary (née Whyte; 1913–2009) and Eric Fletcher Waters (1914–1944), in Great Bookham, Surrey. His father, the son of a coal miner and Labour Party activist, was a schoolteacher, a devout Christian, and a Communist Party member. In the early years of the Second World War, Waters' father was a conscientious objector who drove an ambulance during the Blitz.
Document 13: Idwal Robling: Robling was born in Ynyshir in the Rhondda Valley, where he attended the local grammar school. His education was interrupted by the Second World War, and upon being called up was accepted for service in the Royal Navy. However, he was selected by ballot to become a Bevin Boy so instead of going to the Navy he was conscripted to work in the coal mines. After the war, he resumed his education and qualified as a teacher after attending Caerleon College and Loughborough University, although instead of teaching he decided on a different career and became a manager at the Lovell's sweet factory in Newport, Monmouthshire.
Document 14: The Wall – Live in Berlin: The Wall – Live in Berlin was a live concert performance by Roger Waters and numerous guest artists, of the Pink Floyd studio album "The Wall", itself largely written by Waters during his time with the band. The show was held in Berlin on 21 July 1990, to commemorate the fall of the Berlin Wall eight months earlier. A live album of the concert was released 21 August 1990. A video of the concert was also commercially released.
Document 15: Herbert Graf: Herbert Graf (10 April 1903, Vienna5 April 1973, Geneva) was an Austrian-American opera producer. Born in Vienna in 1903, he was the son of Max Graf (1873–1958), and Olga Hönig. His father was an Austrian author, critic, musicologist and member of Sigmund Freud's circle of friends. Herbert Graf was the Little Hans discussed in Freud's 1909 study "Analysis of a Phobia in a Five-year-old Boy".
ground_truth: Eric Fletcher Waters
sub_queries: What is Botho Graef's birthplace? Answer: Berlin
The Wall – Live in Berlin >> cast member Answer: Roger Waters
The father of Roger Waters was who? Answer: Eric Fletcher Waters