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.

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.

Constraints

• All values in input are integers.
• $1 \leq A \leq B \leq 1000$
• $1 \leq K \leq 1000$

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

见题面 Input 部分

见题面 Output 部分