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 A
{
    class Program
    {
        static void Main(string[] args)
        {
            var k = int.Parse(Console.ReadLine());
            var tmp = Console.ReadLine().Split(' ');
            var a = int.Parse(tmp[0]);
            var b = int.Parse(tmp[1]);
            var flag = false;
            for (int i = 0; i < 1000 / k + 1; i++)
            {
                if(a <= i * k && i * k <= b)
                {
                    flag = true;
                }
            }
            Console.WriteLine(flag ? "OK" : "NG");
        }
    }
}