MathCastle
ChallengeMedium

Challenge · Medium problem

In a round-robin tournament among 77 players, every pair plays once and each game is won by either player with probability 12\dfrac12, independently. A cyclic triple is a set of three players {X,Y,Z}\{X,Y,Z\} with XX beating YY, YY beating ZZ, and ZZ beating XX. If the expected number of cyclic triples is mn\dfrac{m}{n} in lowest terms, find m+nm+n.

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