New York Consolidated Laws, Real Property Actions and Proceedings Law - RPA § 1517. Answer

The defendant may, in his answer, deny any material allegation of the complaint controverted by him, or any knowledge or information thereof sufficient to form a belief, or may set forth facts constituting a defense;  and thereupon he may demand judgment dismissing the complaint.  He may also set forth facts as a counterclaim for the same cause of action;  or the defendant may set forth facts showing that he has an estate or interest in said property;  and thereupon he may demand any judgment to which he would be entitled in an action brought by him to recover that estate or to enforce in any manner the interest which he asserts in such property;  or he may combine any two or more of said demands.