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# (Mono-csc 3.5.0) (judge verdict: Wrong Answer)

using System;

namespace ConsoleApp2
{
    public class Program
    {
        static void Main(string[] args)
        {
            int k, a, b = 0;

            k = int.Parse(Console.ReadLine());
            var buf = Console.ReadLine().Split(' ');
            a = int.Parse(buf[0]);
            b = int.Parse(buf[1]);

            int c = a - a % k + k;
            if (a <= c && c <= b)
            {
                Console.WriteLine("OK");
            }
            else
            {
                Console.WriteLine("NG");
            }
        }
    }
}