Consider a Stackelberg triopoly model with three firms: two leaders and one follower. In the first stage the leaders choose simultaneously their quantities q1 and q2. In the second stage the follower observes the leaders’ quantities and then chooses its quantity q3. Market price is given by the inverse demand function P(Q) = a  Q, where Q = q1 + q2 + q3, and all the firms share same constant marginal costs c. Profits are the payoffs. Find the backwards induction outcome of the game.