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;
using System.Collections.Generic;
class Program
{
 
    static void Main()
    {
        int i=0;
        int K = int.Parse(Console.ReadLine());
        string[] AB = Console.ReadLine().Split(' ');
        int A = int.Parse(AB[0]);
        int B = int.Parse(AB[1]);
 
        
        while(true)
        {
            int L = K;
            i += 1;
            K *= i;
            if(K>B)
            {
                Console.WriteLine("NG");
                break;
            }
            if(K >= A && K<=B)
            {
                if (K >= A && K <= B)
                {
                    Console.WriteLine("OK");
                }
                else
                {
                    Console.WriteLine("NG");
                }
                break;
            }
            K = L;
        }
      
    }
}