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 Python (3.8.2) (judge verdict: Runtime Error)

a, b, n = map(int, input().split())

temp_prev = 0
temp_curr = 0
x = min(n, b-1)

while x <= n:
    temp_prev = temp_curr
    temp_curr = int(a * x / b) - a * int(x / b)
    x += 1.0

    if temp_curr <= temp_prev:
        break

print(max(temp_curr, temp_prev))