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: Accepted)

#!/usr/bin/env python3
import sys
from itertools import chain


def solve(K: int, A: int, B: int):
    n = (A + K - 1) // K
    l = n * K
    if l <= B:
        return "OK"
    return "NG"


def main():
    tokens = chain(*(line.split() for line in sys.stdin))
    K = int(next(tokens))  # type: int
    A = int(next(tokens))  # type: int
    B = int(next(tokens))  # type: int
    answer = solve(K, A, B)
    print(answer)


if __name__ == "__main__":
    main()