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)
	{
		// 整数の入力
		int a = int.Parse(Console.ReadLine());
		// スペース区切りの整数の入力
		string[] input = Console.ReadLine().Split(' ');
		int b = int.Parse(input[0]);
		int c = int.Parse(input[1]);
      
      int i=0;
      bool d = false;
      
      while(a*i <= c){
        if(a*i >= b && a*i <= c){
          d = true;
          break;
        }
        i++;
      }
		//出力
      	if(d){
        	Console.WriteLine("OK");
      	}
      	else{
        	Console.WriteLine("NG");
      	}
	}
}