
import java.util.*;
public class Main {// Main
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);


		int n = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		int q = a/n;
		int q2 = b/n;
		if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		}
		
}
} import java.util.*; util.* java public class Main {// Main
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);


		int n = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		int q = a/n;
		int q2 = b/n;
		if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		}
		
}
} Main public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);


		int n = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		int q = a/n;
		int q2 = b/n;
		if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		}
		
} main {
		Scanner sc = new Scanner(System.in);


		int n = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		int q = a/n;
		int q2 = b/n;
		if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		}
		
} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n 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 int q = a/n; q a/n a n int q2 = b/n; q2 b/n b n if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		} q2>q || a%n==0 q2>q q2 q a%n==0 a%n a n 0 {
			System.out.println("OK");
		} System.out.println("OK") System.out.println System.out System System.out "OK" {
			System.out.println("NG");
		} System.out.println("NG") System.out.println System.out System System.out "NG" String[] args args public class Main {// Main
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);


		int n = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		int q = a/n;
		int q2 = b/n;
		if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		}
		
}
} public class Main {// Main
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);


		int n = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		int q = a/n;
		int q2 = b/n;
		if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		}
		
}
} Main

import java.util.*;
public class Main {// Main
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);


		int n = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		int q = a/n;
		int q2 = b/n;
		if(q2>q || a%n==0) {
			System.out.println("OK");
		}else {
			System.out.println("NG");
		}
		
}
}