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 Rust (1.42.0) (judge verdict: Accepted)

use proconio::input;
use num::integer::*;

fn main() {
  input! {
    k: isize,
    a: isize,
    b: isize,
  }
  // are there k such that a <= k n <= b ?
  let lb = -(-a).div_floor(&k); // n >= lb
  let ub = b.div_floor(&k); // n <= ub
  if lb <= ub {
    println!("OK");
  } else {
    println!("NG");
  }
}