Write a LISP Program to Find GCD of Two Numbers

(DEFUN GCD(X Y)
     (COND((OR(=X 0)(=Y 0)) 0)
          ((<X 0) (GCD(-X) Y)))
          ((<Y 0) (GCD X (-Y)))
          (T(GCD-POSITIVE(X Y)
             (COND((=XY)X)
                  ((>X Y) (GCD-POSITIVE(-X Y)Y))
                  (T(GCD-POSITIVE X(-Y X)))))

           (DEFUN MAIN(X Y)  # Main Program
                (GCD X Y))