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;


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

        if( a > b)
        {
            int temp = a;
            a = b;
            b = temp;
        }

        bool ok = false;
        for(int i = 1; (i*k) <= b; i++)
        {
            if((i*k) >= a & (i*k) <= b)
            {
                ok = true;
                break;
            }
        }

        if( ok)
        {
            Console.WriteLine("OK");
        }
        else
        {
            Console.WriteLine("NG");
        }
    }
}