Section 21: Common expenses to be a charge on the apartment.

All sums assessed by the Association of Apartment Owners, but unpaid for the share of the common expenses chargeable to any apartment, shall constitute a charge on such apartment prior to all other charges except only—

(i) the charge, if any, on the apartment for payment of Government and municipal taxes; and (ii) all the sums unpaid on a first mortgage of the apartment.