11. Rico mortgaged a parcel of land to Maris as security for a loan. In the mortgage contract, Rico appointed Maris as attorney-in-fact for the purpose of selling the land in case of default in the payment of loan. Rico failed to pay his obligation. Maris then purchased the land from Rico through a deed of absolute sale. Later, Rico questioned the mortgage contract because it violates the prohibition against pactum commisorium. As such, the subsequent sale is also void. Is the sale between Rico and Maris valid? Explain.