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 C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Linq;
public class Hello{
    public static void Main()
    {
        //入力Kを保持する
        var K = int.Parse(Console.ReadLine());
        //入力ABを保持する
        var AB = Console.ReadLine().Split().Select(e =>int.Parse(e)).ToArray();
        //AからBに至るまでKの倍数がないかチェックする
        for(var num =AB[0];num <= AB[1];num++)
        {
            if (num % K == 0)
            {
                //もし見つかればOKとしてループを抜け、処理終了
                Console.WriteLine("OK");
                return;
            }
        }
        //見つからなければ、NGとする
        Console.WriteLine("NG");
    }
}