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
  $s = trim(fgets(STDIN));
  $s = str_replace(array("\r\n","\r","\n"), '', $s);
  $s = explode(" ", $s);
    // x = 3のとき、floor(Ax/B)−A × floor(x/B) = floor(15/7)−5 × floor(3/7)=2  となります
    
    //A B N
    // var_dump($s);
    $A = (int)$s[0]; 
    $B = (int)$s[1]; 
    $N = (int)$s[2];
    
    $maximum = 0;
    $calc = 0;
    $prev = -1;
    for ($i = $N; $i >= 1; $i--){
        $calc = floor($A*$i/$B)-$A * floor($i/$B);
        // if ($maximum == $calc) {
        //     break;
        // }
        
        // if ($maximum <= $calc) {
            $maximum = $calc;
            break;
        // }
    }
    
    echo $maximum;


  ?>