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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace I_am_an_idiot
{
    class Program
    {
        static void Main(string[] args)
        {
            int a, b, k;
            string[] s;
            k = Convert.ToInt32(Console.ReadLine());
            s = Console.ReadLine().Split(' ');
            a = Convert.ToInt32(s[0]);
            b = Convert.ToInt32(s[1]);
            for (int i = 1; k * i < b + 1; ++i)
            {
                if (k * i >= a && k * i <= b)
                {
                    Console.WriteLine("OK");
                    return;
                }
            }
            Console.WriteLine("NG");
            return;
        }
    }
}