Sue transferred a building to her newly formed corporation, RSTU Inc. The building had an adjusted basis to Sue of $75,000 and a fair market value of $150,000 on the date of the transfer. The building was encumbered by a mortgage of $100,000, which RSTU Inc. assumed. On the same day, and in exchange for the building she transferred to RSTU Inc., Sue received 100 percent of RSTU Inc.'s only class of stock. The fair market value of the stock at the date of transfer was $50,000. How much gain was recognized by Sue as a result of this transaction?