Please answer this: Extract the answer to the question from the following context. Question: How were the guns aimed to score a hit on the first try? Context: After the Dambusters raid in 1943 an entirely new system was developed that was required to knock down any low-flying aircraft with a single hit. The first attempt to produce such a system used a 50 mm gun, but this proved inaccurate and a new 55 mm gun replaced it. The system used a centralised control system including both search and targeting radar, which calculated the aim point for the guns after considering windage and ballistics, and then sent electrical commands to the guns, which used hydraulics to point themselves at high speeds. Operators simply fed the guns and selected the targets. This system, modern even by today's standards, was in late development when the war ended.
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Answer: a centralised control system

Please answer this: Extract the answer to the question from the following context. Question: Name the city that is ranked third, in the most impressive skyline? Context: Since 2001, Miami has been undergoing a large building boom with more than 50 skyscrapers rising over 400 feet (122 m) built or currently under construction in the city. Miami's skyline is ranked third-most impressive in the U.S., behind New York City and Chicago, and 19th in the world according to the Almanac of Architecture and Design. The city currently has the eight tallest (as well as thirteen of the fourteen tallest) skyscrapers in the state of Florida, with the tallest being the 789-foot (240 m) Four Seasons Hotel & Tower.
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Answer: Miami

Please answer this: Extract the answer to the question from the following context. Question: During what century did Hindu Shahis take command of the dynasties? Context: The Kabul Shahi dynasties ruled the Kabul Valley and Gandhara (modern-day Pakistan and Afghanistan) from the decline of the Kushan Empire in the 3rd century to the early 9th century. The Shahis are generally split up into two eras: the Buddhist Shahis and the Hindu Shahis, with the change-over thought to have occurred sometime around 870. The kingdom was known as the Kabul Shahan or Ratbelshahan from 565-670, when the capitals were located in Kapisa and Kabul, and later Udabhandapura, also known as Hund for its new capital.
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Answer:
9th century