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-----
7
500 600

-----Sample Output-----
OK

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

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