Portia and Dina entered into an oral contract wherein Dina agreed to the sale of Lot 1 to Portia for the price of P2,000,000. It turned out that at the time Portia and Dina agreed upon the sale, Dina was not the owner of Lot 1. Later on, Portia asked Dina to deliver the lot to her but Dina refused. Portia filed an action for specific performance against Dina. Dina filed a motion to dismiss on the ground that she cannot be compelled to perform the contract since it was not in writing. Is the contract of sale valid? Explain.