Directed Graphs and Network Flows · Medium problem

In the $5$-team tournament with results $1\to2$, $2\to3$, $3\to1$, $1\to4$, $4\to2$, $3\to4$, $1\to5$, $5\to2$, $5\to3$, $4\to5$, how many sets of three teams $\{x,y,z\}$ form a genuine $3$-cycle (each of the three beats exactly one of the other two)?