import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		}
	}
} Main public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		}
	} main {
		try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		}
	} try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		} {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		} Scanner scanner = new Scanner(System.in) Scanner scanner = new Scanner(System.in) new Scanner(System.in) int k = scanner.nextInt(); k scanner.nextInt() scanner.nextInt scanner int a = scanner.nextInt() a scanner.nextInt() scanner.nextInt scanner b = scanner.nextInt(); b scanner.nextInt() scanner.nextInt scanner System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG") System.out.println System.out System System.out ((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG" ((0 == (a % k)) || ((a / k) != (b / k))) (0 == (a % k)) 0 (a % k) a k ((a / k) != (b / k)) (a / k) a k (b / k) b k "OK" "NG" String[] args args public class Main {

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		}
	}
} public class Main {

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		}
	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int k = scanner.nextInt();
			int a = scanner.nextInt(), b = scanner.nextInt();
			System.out.println(((0 == (a % k)) || ((a / k) != (b / k))) ? "OK" : "NG");
		}
	}
}
