Consider a hypothetical perfectly competitive market for identical lunch boxes supplied to Monash students. All firms have TC=200+\frac12q^2, and market demand is Q_D=600-10P. Firms face identical costs, and entry and exit are free in the long run. Find the number of firms in the initial long-run equilibrium.

Please enter a number only. If your answer is a decimal, round it to no more than two decimal places. Do not include spaces, commas, letters, or special characters such as dollar signs.