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

public class Main {
    public static void main(String args[]) throws IOException {

	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int K = Integer.parseInt(br.readLine());
	String[] array = br.readLine().split(" ");

	int A = Integer.parseInt(array[0]), B = Integer.parseInt(array[1]);

	String result = "NG";
	for (int i = A; i <= B; i++) {
	    if (i % K == 0) {
		result = "OK";
		break;
	    }
	}
	System.out.println(result);
    }
} 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 {

	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int K = Integer.parseInt(br.readLine());
	String[] array = br.readLine().split(" ");

	int A = Integer.parseInt(array[0]), B = Integer.parseInt(array[1]);

	String result = "NG";
	for (int i = A; i <= B; i++) {
	    if (i % K == 0) {
		result = "OK";
		break;
	    }
	}
	System.out.println(result);
    }
} Main public static void main(String args[]) throws IOException {

	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int K = Integer.parseInt(br.readLine());
	String[] array = br.readLine().split(" ");

	int A = Integer.parseInt(array[0]), B = Integer.parseInt(array[1]);

	String result = "NG";
	for (int i = A; i <= B; i++) {
	    if (i % K == 0) {
		result = "OK";
		break;
	    }
	}
	System.out.println(result);
    } main {

	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int K = Integer.parseInt(br.readLine());
	String[] array = br.readLine().split(" ");

	int A = Integer.parseInt(array[0]), B = Integer.parseInt(array[1]);

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

	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int K = Integer.parseInt(br.readLine());
	String[] array = br.readLine().split(" ");

	int A = Integer.parseInt(array[0]), B = Integer.parseInt(array[1]);

	String result = "NG";
	for (int i = A; i <= B; i++) {
	    if (i % K == 0) {
		result = "OK";
		break;
	    }
	}
	System.out.println(result);
    }
} public class Main {
    public static void main(String args[]) throws IOException {

	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int K = Integer.parseInt(br.readLine());
	String[] array = br.readLine().split(" ");

	int A = Integer.parseInt(array[0]), B = Integer.parseInt(array[1]);

	String result = "NG";
	for (int i = A; i <= B; i++) {
	    if (i % K == 0) {
		result = "OK";
		break;
	    }
	}
	System.out.println(result);
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String args[]) throws IOException {

	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	int K = Integer.parseInt(br.readLine());
	String[] array = br.readLine().split(" ");

	int A = Integer.parseInt(array[0]), B = Integer.parseInt(array[1]);

	String result = "NG";
	for (int i = A; i <= B; i++) {
	    if (i % K == 0) {
		result = "OK";
		break;
	    }
	}
	System.out.println(result);
    }
}