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 std::io;

fn read_line() -> String {
    let mut buf = String::new();
    io::stdin().read_line(&mut buf).expect("");
    buf.trim().to_string()
}

fn read_i32() -> i32 {
    read_line().parse().expect("")
}

fn read_vi32() -> Vec<i32> {
    read_line().split(' ').into_iter()
        .map(|w| w.parse().expect(""))
        .collect()
}

fn main() {
    let k = read_i32();
    if let &[a, b] = &read_vi32()[..] {
        println!("{}",
                 if a <= b / k * k {
                     "OK"
                 } else {
                     "NG"
                 }
                );
    }
}