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: Wrong Answer)

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

namespace Program1
{
    class Program
    {
        static void Main(string[] args)
        {

            var line = Console.ReadLine();
            var num = int.Parse(line);  //K倍

            var line2 = Console.ReadLine();
            var num2 = line2.Split(' ');
            var A = int.Parse(num2[0]); //A
            var B = int.Parse(num2[1]); //B (A <= Kx <= B)
            int i = 1;
            while (true)
            {
               


                if ((A<=num && num <= B) || num ==1)
                {
                    Console.WriteLine("OK");
                    break;
                }
                if (num > B)
                {
                    Console.WriteLine("NG");
                    break;

                }

                num *= i;
                i++;


            }

        }
    }
}