Problem:
Score: 100 points

Problem Statement

Takahashi the Jumbo will practice golf.

His objective is to get a carry distance that is a multiple of K, while he can only make a carry distance of between A and B (inclusive).

If he can achieve the objective, print OK; if he cannot, print NG.

Constraints

All values in input are integers.

1 \leq A \leq B \leq 1000

1 \leq K \leq 1000

Input

Input is given from Standard Input in the following format:

K
A B

Output

If he can achieve the objective, print OK; if he cannot, print NG.

Sample Input 1

7
500 600

Sample Output 1

OK

Among the multiples of 7, for example, 567 lies between 500 and 600.

Sample Input 2

4
5 7

Sample Output 2

NG

No multiple of 4 lies between 5 and 7.

Sample Input 3

1
11 11

Sample Output 3

OK

Solution in Common Lisp (SBCL 2.0.3) (judge verdict: Accepted)

;;(declaim (optimize (speed 0) (safety 3) (debug 3)))
#+sbcl (declaim (sb-ext:unmuffle-conditions sb-ext:compiler-note))
(declaim (optimize (speed 3) (safety 0) (debug 0)))

(defvar k (read))
(defvar min-d (read))
(defvar max-d (read))

(format t "~:[NG~;OK~]" (<= (ceiling min-d k) ;; min multiple of k ge min-d
			    (floor max-d k))) ;; max mutiple of k le max-d