(defn right_zeros
  [np]
    (loop [z 0 n np]
	    (if (or (< n 10) (not= (mod n 10) 0))
			z
			(recur (inc z) (/ n 10)))))


(println (right_zeros 123000))
(println (right_zeros 102030))
(println (right_zeros 123123))
(println (right_zeros 10))
(println (right_zeros 0))
(println (right_zeros 1))