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;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp55
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = int.Parse(Console.ReadLine());//.Split(' ').Select(int.Parse)
            var ab = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();

            for ( var i = 1; i< 1000; i++)
            {
                var r = check(N * i, ab);
                if (r== 1)
                {
                    Console.WriteLine("OK");
                    return;
                }
                
            }
            Console.WriteLine("NG");



        }
        static int  check (int c ,int[] ab ){

            if ( ab[1]< c)
                return -1;
            return ab[0] <= c && c <= ab[1] ? 1 :  0;


            }
    }
}