How to solve this problem and what is the formula?

Janice Corporation processes direct materials up to the split-off point, where products R and S are produced and thereafter sold. For the month just ended, the following information were made available

Direct materials, 20,000 gallons (yield - 19,000 gallons of good product and 1,000 gallons of shrinkage)

Production: R, 10,000 gallons; S, 9,000 gallons.

Unit selling price: R, P 1,500 per gallon; S, P 1,000 per gallon.

The cost of buying 20,000 gallons of direct materials and processing up to split-off point to yield a total of 19,000 gallons of good products was P 19,500,000. The beginning inventories totaled 100 gallons for R and 50 gallons for S. Ending inventories amounts reflected 600 gallons for R and 1,050 gallons for S.

Using the volume of production as the basis for allocating joint costs, the assigned costs to R and S would be ____________