Whoever knowingly deposits for mailing or delivery, or knowingly causes to be delivered by mail, according to the direction thereon, or at any place at which it is directed to be delivered by the person to whom it is addressed, anything declared nonmailable by section 3014(b) of title 39, unless in accordance with the rules and regulations prescribed by the Postal Service under section 3014(c) of such title, shall be fined under this title, or imprisoned not more than one year, or both.