Caliente Company uses process costing. At the beginning of the month, there were 3,000 units in process, 70% complete with respect to material and 60% complete with respect to conversion costs. 20,000 units were started during the month and 20,000 units were completed. The units in ending work in process inventory were 90% complete with respect to material and 30% complete with respect to conversion costs. How many equivalent units will be used in calculating the cost per unit for materials?