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 PHP (7.4.4) (judge verdict: Wrong Answer)

<?php
$n = trim(fgets(STDIN));
$arr = explode(' ', trim(fgets(STDIN)));
$a = $arr[0];
$b = $arr[1];

$c = floor($a / $n);

$d = $n * ($c + 1);

if ($n == $a){
    echo 'OK';
    return;
}

if ($n == $b){
    echo 'OK';
    return;
}

if ($a <= $d && $b >= $d){
    echo 'OK';
    return;
}

if ((($b - $a) + 1) >= $n) {
    echo 'OK';
    return;
}

echo 'NG';
    return;

?>