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 ConsoleApp2
{
    class Program
    {
        static void Main()
        {
            int a, b, i, j, k;
            string ab;
            bool gflag = false;

            k = int.Parse(Console.ReadLine());
            ab = Console.ReadLine();

            i = ab.IndexOf(" ");

            if (i >= 0)
            {
                a = int.Parse(ab.Substring(0, i));
                b = int.Parse(ab.Substring(i + 1));

                for (j = a; j <= b; j++)
                {
                    if ((j % k) == 0)
                    {
                        gflag = true;
                        break;
                    }
                }
            }
            if (gflag)
            {
                Console.WriteLine("OK");
            }
            else
            {
                Console.WriteLine("NG");
            }

        }
    }
}