40891
Sweeping is done for several reasons : to make the stone travel farther , to decrease the amount of curl , and to clean debris from the stone 's path. Sweeping is able to make the stone travel farther and straighter by slightly melting the ice under the brooms , thus decreasing the friction as the stone travels across that part of the ice .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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