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)

//---------- Begin IO utilities ----------
#[macro_use]
#[allow(dead_code, unused_macros)]
mod io {
    // Thanks to https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
    macro_rules! input {
        ($($r:tt)*) => {
            let s = {
                use std::io::Read;
                let mut s = String::new();
                std::io::stdin().read_to_string(&mut s).unwrap();
                s
            };
            let mut iter = s.split_whitespace();
            input_inner!{iter, $($r)*}
        };
    }
    macro_rules! input_inner {
        ($iter:expr) => {};
        ($iter:expr, ) => {};
        ($iter:expr, $var:tt : $t:tt $($r:tt)*) => {
            let $var = read_value!($iter, $t);
            input_inner!{$iter $($r)*}
        };
    }
    macro_rules! read_value {
        ($iter:expr, ( $($t:tt),* )) => {
            ( $(read_value!($iter, $t)),* )
        };
        ($iter:expr, [ $t:tt ; $len:expr ]) => {
            (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
        };
        ($iter:expr, chars) => {
            read_value!($iter, String).chars().collect::<Vec<char>>()
        };
        ($iter:expr, usize1) => {
            read_value!($iter, usize) - 1
        };
        ($iter:expr, $t:ty) => {
            $iter.next().unwrap().parse::<$t>().expect("Parse error")
        };
    }

    macro_rules! p {
        ($v:expr) => {
            println!("{}", $v);
        };
        ($v:expr, $($t:expr),*) => {
            print!("{}", $v);
            ($(print!(" {}", $t)),*);
            println!();
        }
    }

    macro_rules! ps {
        ($v:expr) => {
            println!("{}", $v.iter().collect::<String>());
        };
        ($v:expr, $($t:expr),*) => {
            print!("{}", $v.iter().collect::<String>());
            ($(print!(" {}", $t.iter().collect::<String>())),*);
            println!();
        }
    }

    pub fn pv<T: std::string::ToString>(v: &[T], sep: &str) {
        let s = v.iter().map(|e| e.to_string()).collect::<Vec<String>>().join(sep);
        println!("{}", s);
    }

    pub fn pvs(v: &[Vec<char>], sep:&str) {
        let s = v.iter().map(|e| e.iter().collect::<String>()).collect::<Vec<String>>().join(sep);
        println!("{}", s);
    }
}
//---------- End IO utilities ----------

//---------- Start solve ----------
#[allow(unused_imports)]
use io::*;
fn main() {
    input!{
        k: usize,
        a: usize,
        b: usize
    }
    for i in a..=b {
        if i % k == 0 {
            p!("OK");
            return;
        }
    }
    p!("NG");
}