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;

class Program
{
    static void Main(string[] args)
    {
        var a = long.Parse(Console.ReadLine());
        var b = Console.ReadLine().Split(" ");
        var times = 1000 / a + 1;
        for (var i = 1;  times >= i; i++)
        {
            if (int.Parse(b[0]) < a * i && a * i < int.Parse(b[1]))
            {
                Console.WriteLine("OK");
                break;
            }
            if (i == times)
            {
                Console.WriteLine("NG");
                break;
            }
        }
    }
}