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 OCaml (4.10.0) (judge verdict: Accepted)

open Batteries

let len = Scanf.scanf "%d\n" (
        fun k -> 
                Scanf.scanf "%d %d" (
                        fun a b -> 
                                List.range a `To b
                                |> List.filter (fun x -> x mod k = 0)
                )
) |> List.length
 
let () = Printf.printf "%s\n" (if len = 0 then
                                       "NG"
                               else
                                       "OK"
                              )