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: Runtime Error)

using System;


class Program
{
    static void Main(string[] args)
    {
        int k, a, b;
        if (int.TryParse(Console.ReadLine(), out k))
        {
            string[] s = Console.ReadLine().Split(" ");
            if (int.TryParse(s[0], out a) & int.TryParse(s[1], out b))
            {
                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");
                }
            }
        }
        Console.ReadKey();
    }
}