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.Numerics;

namespace ConsoleApp1
{
    class Program
    {
        static void Main()
        {
            int k = int.Parse(Console.ReadLine());
            string ab = Console.ReadLine();
            int a = int.Parse(ab.Split(" ")[0]);
            int b = int.Parse(ab.Split(" ")[1]);

            bool exist = false;

            for (int i = a; i <= b; i++)
            {
                if(i % k == 0)
                {
                    exist = true;
                    break;
                }
            }

            string result = "NG";
            if(exist)
            {
                result = "OK";
            }

            Console.WriteLine(result);
        }

    }
}