=+20. In our discussion of Stirling numbers of the first kind, we showed that the number of left-to-right maxima Yn of a random permutation has the decomposition Yn = Z1 +···+Zn, where the Zk are independent Bernoulli variables with decreasing success probabilities. Prove that Zk can be interpreted as the indicator of the event that position n−k+1 is a left-to-right maximum. In other words, Zk is the indicator of the event {π(n − k + 1) > π(j) for 1 ≤ j