The owner of a convenience store is considering adding a take-out sandwich section to her offerings. The new activity will occupy 25% of the space currently being rented out to a milk tea stall for P28,000 per month. The milk tea stall owner agreed to rent the remaining 75% of the space for P19,300. How much opportunity cost should be included in estimating the cash flow of the take-out sandwich section? Indicate negative sign if cash outflow.