Donald and Melania agree to go into business together. Donald will contribute a building with a FMV of $600,000 and a tax basis of $200,000 in return for 50 percent of the stock in the corporation. The corporation will assume a $300,000 mortgage on the building. Melania will contribute $300,000 cash in return for 50% of the stock of the corporation. How much gain, if any, does Donald recognize on the transfer of his building assuming the transaction qualifies under IRC Section 351?