The first modern Olympics of 1896 had a marathon distance of 40 km. In 1908, for the Olympic marathon in London, the length was set at 42.195 km to provide the Royal Family with a better view of the race. Other distances were 40.26 km (1900), 41.86 km (1906), 40.2 km (1912), and 42.75 km (1920). In 1921, the International Amateur Athletic Federation adopted the distance of 42.195 km as the official length. What was the length of the 1920 marathon, in miles?
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