Consider a market for refrigerators. Suppose that the price elasticity is such that b = 1/500, fixed cost F = $50,000,000 and a marginal cost of c = $100 per refrigerator. Suppose Home country has annual sales of 1 million refrigerators; Foreign country has annual sales of 2 million refrigerators; and a Third country has annual sales of 3 million refrigerators. The number of firms in the Third country before any integration of markets is _