Variable costs for a product is $60 and fixed costs (including staff salaries, and maintenance) amount to $4000 per month. The price of product A is $113. The company operates only 26 days a month and produces 125 units per day. But during one-weekday demand was 115 units. The cost of lost sales is $9 per unit. Leftover products can be sold for $50 per unit. What was the cost of lost sales?