Acme stamping produces seat brackets for a major manufacturer of stadium seating. They sell an average of 70,000 brackets per year. Their stamping machine operates for 8 hours per day, 250 days per year and can produce 150 brackets per hour. It costs them $400 to set up the stamping machine for a production run. The brackets cost $0.47 each to make, and Acme uses 10% of the unit cost to estimate the annual inventory holding cost. Calculate the economic production quantity for seat brackets.