Question 4: Zoltan is not only your friendly TA, he is also the owner of the popular budget airline ZoltanJet that offers flights in Canada. As you all know, there are n airports in Canada. We denote these airports, in order from west to east, by A1,A2,,An. William, who is the CEO of ZoltanJet, has designed a flight plan which is a list of ordered pairs (Ai,Aj) of airports such that there is a direct flight from Ai to Aj. This flight plan has the following two properties: - (P.1) Every flight is going eastwards 1. In other words, if (Ai,Aj) is in the flight plan, then i