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()
    {
        int k = int.Parse(Console.ReadLine());
        string[] In = Console.ReadLine().Split(' ');
        int a = int.Parse(In[0]);
        int b = int.Parse(In[1]);
        bool flag = false;
        for(int i=1; i<=1000;i++)
        {
            if (b<k*i) break;
            if (a <= k * i & k * i <= b) { flag = true; break; }
        }
        if (flag) Console.WriteLine("OK");
        else Console.WriteLine("NG");
    }
}