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-mcs 6.8.0.105) (judge verdict: Wrong Answer)

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


    class Program
    {
        static void Main(string[] args)
        {
            long K = long.Parse(Console.ReadLine());
            string[] Input = Console.ReadLine().Split(' ');
            long A = long.Parse(Input[0]);
            long B = long.Parse(Input[1]);
            bool OK = false;
            
            long count = 1;
            do
            {
                if(count * K >= A && count * K <= B){
                    OK = true;
                } 
                count++;
            }while(count * K <= B);
            
            if(OK){
                Console.WriteLine("OK");
            }else{
                Console.WriteLine("NO");
            }
        }
    }