The subject first-priority clause (article [5], paragraph [3] [e]) is clear and unambiguous and does not contain the terms added by the motion court. "In adjudicating the rights of parties to a contract, courts may not fashion a new contract under the guise of contract construction" ( Slatt v Slatt, 64 NY2d 966, 967). Nor may they "`imply a condition which the parties chose not to insert in their contract'" ( Nichols v Nichols, 306 NY 490, 496 [1954]).