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 Ruby (2.7.1) (judge verdict: Accepted)

def main(str)
  lines = str.split("\n").map { |x| x.split(" ").map(&:to_i) }
  k = lines[0][0]
  a, b = lines[1]
  n = 0
  loop do
    return "OK" if (a..b).include?(n)
    return "NG" if b < n
    n += k
  end
end

unless ENV["TEST"]
  puts(main($stdin.read.chomp))
  exit(0)
end

require 'minitest/autorun'

class TestA < Minitest::Test
  def test_main
    assert_equal("OK", main("7
500 600"))
    assert_equal("NG", main("7
500 501"))
  end
end