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;

namespace welovegolf
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = "NG";
            int k = int.Parse(Console.ReadLine());
            string[] input = Console.ReadLine().Split(' ');
            int a = int.Parse(input[0]);
            int b = int.Parse(input[1]);

            int r = a / k;

            if ((k * r >= a && k * r <= b) || (k  * (r + 1) >= a && k * (r + 1) <= b) || (k * (r - 1) >= a && k * (r - 1) <= b))
                s = "OK";

            Console.WriteLine(s);
        }
    }
}