import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

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

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

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

        br.close();

        String ans = "NG";

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

        bw.write(ans);

        bw.flush();

    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.BufferedWriter; BufferedWriter java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.OutputStreamWriter; OutputStreamWriter java.io public class Main {
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

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

        br.close();

        String ans = "NG";

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

        bw.write(ans);

        bw.flush();

    }
} Main public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

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

        br.close();

        String ans = "NG";

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

        bw.write(ans);

        bw.flush();

    } main {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

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

        br.close();

        String ans = "NG";

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

        bw.write(ans);

        bw.flush();

    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out)); bw new BufferedWriter(new OutputStreamWriter(System.out)) int k = Integer.parseInt(br.readLine()); k Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br String[] in = br.readLine().split(" "); in br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int a = Integer.parseInt(in[0]); a Integer.parseInt(in[0]) Integer.parseInt Integer in[0] in 0 int b = Integer.parseInt(in[1]); b Integer.parseInt(in[1]) Integer.parseInt Integer in[1] in 1 br.close() br.close br String ans = "NG"; ans "NG" for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                ans = "OK";
            }
        } int i = a; int i = a; i a i <= b i b i++ i++ i {
            if (i % k == 0) {
                ans = "OK";
            }
        } {
            if (i % k == 0) {
                ans = "OK";
            }
        } if (i % k == 0) {
                ans = "OK";
            } i % k == 0 i % k i k 0 {
                ans = "OK";
            } ans = "OK" ans "OK" bw.write(ans) bw.write bw ans bw.flush() bw.flush bw String[] args args public class Main {
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

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

        br.close();

        String ans = "NG";

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

        bw.write(ans);

        bw.flush();

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

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

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

        br.close();

        String ans = "NG";

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

        bw.write(ans);

        bw.flush();

    }
} Main
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

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

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

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

        br.close();

        String ans = "NG";

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

        bw.write(ans);

        bw.flush();

    }
}