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: Runtime Error)

(defmacro while (test &body body)                                                                                                                                                                         
 2  `(do ()                                                                                                                                                                                                 
 3       ((not ,test))                                                                                                                                                                                      
 4     ,@body))                                                                                                                                                                                             
 5                                                                                                                                                                                                          
 6(defun main ()                                                                                                                                                                                            
 7  (let ((k (read))                                                                                                                                                                                        
 8        (a (read))                                                                                                                                                                                        
 9        (b (read))                                                                                                                                                                                        
10        (ans "NG"))                                                                                                                                                                                       
11    (while (<= a b)                                                                                                                                                                                       
12      (when (zerop (rem a k))                                                                                                                                                                             
13        (setf ans "OK")                                                                                                                                                                                   
14        (return))                                                                                                                                                                                         
15      (incf a))                                                                                                                                                                                           
16    (format t "~a~%" ans)))                                                                                                                                                                               
17                                                                                                                                                                                                          
18(main)