import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException {
		try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		}
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
	public static void main(String[] args) throws IOException {
		try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		}
	}
} Main public static void main(String[] args) throws IOException {
		try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		}
	} main {
		try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		}
	} try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		} {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		} BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in)) BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in)) new BufferedReader(
				new InputStreamReader(System.in)) int k = Integer.parseInt(br.readLine()); k Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br String in = br.readLine(); in br.readLine() br.readLine br String chr[] = in.split(" "); chr in.split(" ") in.split in " " int a = Integer.parseInt(chr[0]); a Integer.parseInt(chr[0]) Integer.parseInt Integer chr[0] chr 0 int b = Integer.parseInt(chr[1]); b Integer.parseInt(chr[1]) Integer.parseInt Integer chr[1] chr 1 String ans = "NG"; ans "NG" for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			} int i = a; int i = a; i a i <= b i b i++ i++ i {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			} {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			} if (i % k == 0) {
					ans = "OK";
					break;
				} i % k == 0 i % k i k 0 {
					ans = "OK";
					break;
				} ans = "OK" ans "OK" break; System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
	public static void main(String[] args) throws IOException {
		try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		}
	}
} public class Main {
	public static void main(String[] args) throws IOException {
		try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		}
	}
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException {
		try (BufferedReader br = new BufferedReader(
				new InputStreamReader(System.in))) {

			int k = Integer.parseInt(br.readLine());
			String in = br.readLine();
			String chr[] = in.split(" ");
			int a = Integer.parseInt(chr[0]);
			int b = Integer.parseInt(chr[1]);
			String ans = "NG";

			for (int i = a; i <= b; i++) {
				if (i % k == 0) {
					ans = "OK";
					break;
				}
			}
			System.out.println(ans);
		}
	}
}