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)

import sys;input=lambda:sys.stdin.readline().rstrip();aint=lambda:int(input());ints=lambda:list(map(int,input().split()))
import math;floor,ceil=lambda x:int(math.floor(x)),lambda x:int(math.ceil(x))
from functools import reduce;gcd=lambda*x:reduce(math.gcd,x);lcm=lambda*x:reduce(lambda x,y:(x*y)//gcd(x,y),x,1)
from collections import deque
Yes=lambda b:print("Yes"if b else"No");YES=lambda b:print("YES"if b else"NO")
is_even=lambda x:True if x%2==0 else False

def main():
  k=aint();a,b=ints()
  ans=0
  for i in range(a,b+1):
    if i%k==0:
      ans+=1
      break
  print("OK"if ans>0 else"NG")

if __name__ == '__main__':
    main()