If, within twenty years after the completion of construction (as determined by the Secretary of Health, Education, and Welfare) of the new hospital facilities authorized by section 126 of this title, any of such facilities, or of the facilities transferred pursuant to section 124 of this title and combined with such new facilities, are transferred by Howard University to any other person or entity (except a transfer to the United States) or cease to be operated by the university as teaching hospital facilities, the United States shall be entitled to recover from the transferee or the university, in the case of a transfer, or from the university, if there is no transfer, an amount equal to the then value of such facilities (or so much thereof as is involved in the transfer, as the case may be), such value to be determined by agreement of the parties or by action brought in the United States District Court for the District of Columbia.