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.Collections.Generic;
using System.Linq;

class Progaram
{
    static void Main(String[] args)
    {
        var k = Int32.Parse(Console.ReadLine());
        var l = Console.ReadLine().Split(' ').Select(x => Int32.Parse(x)).ToArray();
        var r = 0; var s = k;
        while (s<= l[1])
        {
            r++;
            s = k * r;
            if (s >= l[0] && s <= l[1])
            {
                Console.WriteLine("OK");
                return;
            }
        }
        Console.WriteLine("NG");
    }
}