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;
using System.Linq;

namespace _20200502
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] inputLongArray = Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();


            int x = inputLongArray[0] / n;//商
            int y = inputLongArray[0] % n;//あまり

            int a = inputLongArray[0] - n * x;
            int b = inputLongArray[1] - n * x;

            if (n<= inputLongArray[1]+1 - inputLongArray[0] ) { Console.WriteLine("OK"); }
            else if (a == n) { Console.WriteLine("OK"); }
            else if (b == n) { Console.WriteLine("OK"); }
            else if (a == 0) { Console.WriteLine("OK"); }
            else if (b == 0) { Console.WriteLine("OK"); }
            else if (a< n && b < n) { Console.WriteLine("NG"); }
            else
            { 
                Console.WriteLine("EROOR"); 
            
            
            }

        }
    }
}