import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();
		if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		}
		System.out.println("NG");
	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();
		if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		}
		System.out.println("NG");
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();
		if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		}
		System.out.println("NG");
	} main {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();
		if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		}
		System.out.println("NG");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int k = sc.nextInt(); k sc.nextInt() sc.nextInt sc int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc sc.close() sc.close sc if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		} a > k a k {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} if(b / k >= 2) {
				System.out.println("OK");
				return;
			} b / k >= 2 b / k b k 2 {
				System.out.println("OK");
				return;
			} System.out.println("OK") System.out.println System.out System System.out "OK" return; if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		} a == k a k {
			System.out.println("OK");
			return;
		} System.out.println("OK") System.out.println System.out System System.out "OK" return; if(b >= k){
			System.out.println("OK");
			return;
		} b >= k b k {
			System.out.println("OK");
			return;
		} System.out.println("OK") System.out.println System.out System System.out "OK" return; System.out.println("NG") System.out.println System.out System System.out "NG" String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();
		if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		}
		System.out.println("NG");
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();
		if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		}
		System.out.println("NG");
	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int k = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();
		if(a > k) {
			if(b / k >= 2) {
				System.out.println("OK");
				return;
			}
		} else if(a == k) {
			System.out.println("OK");
			return;
		} else if(b >= k){
			System.out.println("OK");
			return;
		}
		System.out.println("NG");
	}
}
