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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sca = new Scanner(System.in);
		int k = sca.nextInt();
		int a = sca.nextInt();
		int b = sca.nextInt();

		int count = 2;
		boolean flag = false;
		for(int i = k; i <= b; i = k*count) {
			if(a <= i && i <= b) {
				flag = true;
				break;
			}
			count++;
		}

		if(flag) {
			System.out.println("OK");
		}
		else {
			System.out.println("NG");
		}

		// 後始末
		sca.close();
	}
}