Three years ago, Jack and Mary, having been married for 3 years, agreed to purchase some real property and titled it as joint tenants with right of survivorship. At the time of the purchase, Mary did not have any cash, so Jack paid the $50,000 purchase price himself. Over the next five years, Jack and Mary allocated the income and expenses of the property equally, and luckily for them the value of the property increased to $350,000. If Jack dies this year, how much will his executor include in his federal gross estate as the value of this real property