During a period, Department A finished and transferred 50,000 units to Department B. Of the 50,000 units, 20,000 were one-fifth complete with respect to direct labor at the beginning of the period and 30,000 were started and completed during the period. Also, during the period, 10,000 units were started but brought only to a stage of being three-fifths completed. Using the FIFO inventory valuation method, the number of equivalent units produced by Department A during the period was?