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The 2nd Universal Cup Finals is coming! Check out our event page, schedule, and competition rules!
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ucup-team5027
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Southern University of Science and Technology
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Benson's Identity: $$\dbinom{n}{2k}2^{2k}=\sum\limits_{i=0}^k(-1)^i\dbinom{n}{i}\dbinom{2n-2i}{2k-2i}$$