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;
using System.IO;

namespace ABC
{
    class ABC165A
    {
        const bool TESTING = false;
        const string FILE = "/tmp/data.txt";

        static void Main(string[] args)
        {
            if (TESTING)
            {
                Console.SetIn(new StreamReader(FILE));
            }
            var line = Console.ReadLine();
            int k = int.Parse(line);
            line = Console.ReadLine();
            var sa = line.Split(' ');
            int a = int.Parse(sa[0]);
            int b = int.Parse(sa[1]);
            proc(k, a, b);
#if DEBUG
            Console.WriteLine();
#endif
        }

        private static void proc(int k, int a, int b)
        {
            for (int ki = k; ki <= 1000; ki += k)
            {
                if (a <= ki && ki <= b)
                {
                    Console.WriteLine("OK");
                    return;
                }
            }
            Console.WriteLine("NG");
        }
    }
}