Task: Question Answering
Input (English): Sentence: Montana contains thousands of named rivers and creeks, 450 miles (720 km) of which are known for "blue-ribbon" trout fishing. Montana's water resources provide for recreation, hydropower, crop and forage irrigation, mining, and water for human consumption. Montana is one of few geographic areas in the world whose rivers form parts of three major watersheds (i.e. where two continental divides intersect). Its rivers feed the Pacific Ocean, the Gulf of Mexico, and Hudson Bay. The watersheds divide at Triple Divide Peak in Glacier National Park. 
Question: How many miles of rivers are known for high class trout?
Output (English): 450