import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Main {

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

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        int k = Integer.valueOf(mylist.get(0));
        int a = Integer.valueOf(mylist.get(1).split(" ")[0]);
        int b = Integer.valueOf(mylist.get(1).split(" ")[1]);

        Boolean chkflg = false;
        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        }
        System.out.println(chkflg ? "OK" : "NG");

    }

} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util public class Main {

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

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        int k = Integer.valueOf(mylist.get(0));
        int a = Integer.valueOf(mylist.get(1).split(" ")[0]);
        int b = Integer.valueOf(mylist.get(1).split(" ")[1]);

        Boolean chkflg = false;
        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        }
        System.out.println(chkflg ? "OK" : "NG");

    }

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

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        int k = Integer.valueOf(mylist.get(0));
        int a = Integer.valueOf(mylist.get(1).split(" ")[0]);
        int b = Integer.valueOf(mylist.get(1).split(" ")[1]);

        Boolean chkflg = false;
        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        }
        System.out.println(chkflg ? "OK" : "NG");

    } main {

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        int k = Integer.valueOf(mylist.get(0));
        int a = Integer.valueOf(mylist.get(1).split(" ")[0]);
        int b = Integer.valueOf(mylist.get(1).split(" ")[1]);

        Boolean chkflg = false;
        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        }
        System.out.println(chkflg ? "OK" : "NG");

    } InputStreamReader is = new InputStreamReader(System.in); is new InputStreamReader(System.in) BufferedReader reader = new BufferedReader(is); reader new BufferedReader(is) List<String> mylist = new ArrayList<>(); mylist new ArrayList<>() String strinput = reader.readLine(); strinput reader.readLine() reader.readLine reader while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        } strinput != null strinput null {

            mylist.add(strinput);
            strinput = reader.readLine();

        } mylist.add(strinput) mylist.add mylist strinput strinput = reader.readLine() strinput reader.readLine() reader.readLine reader int k = Integer.valueOf(mylist.get(0)); k Integer.valueOf(mylist.get(0)) Integer.valueOf Integer mylist.get(0) mylist.get mylist 0 int a = Integer.valueOf(mylist.get(1).split(" ")[0]); a Integer.valueOf(mylist.get(1).split(" ")[0]) Integer.valueOf Integer mylist.get(1).split(" ")[0] mylist.get(1).split(" ") mylist.get(1).split mylist.get(1) mylist.get mylist 1 " " 0 int b = Integer.valueOf(mylist.get(1).split(" ")[1]); b Integer.valueOf(mylist.get(1).split(" ")[1]) Integer.valueOf Integer mylist.get(1).split(" ")[1] mylist.get(1).split(" ") mylist.get(1).split mylist.get(1) mylist.get mylist 1 " " 1 Boolean chkflg = false; chkflg false for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        } int i = a; int i = a; i a i <= b i b i++ i++ i {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        } {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        } if (i % k == 0) {
                chkflg = true;
                break;
            } i % k == 0 i % k i k 0 {
                chkflg = true;
                break;
            } chkflg = true chkflg true break; System.out.println(chkflg ? "OK" : "NG") System.out.println System.out System System.out chkflg ? "OK" : "NG" chkflg "OK" "NG" String[] args args public class Main {

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

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        int k = Integer.valueOf(mylist.get(0));
        int a = Integer.valueOf(mylist.get(1).split(" ")[0]);
        int b = Integer.valueOf(mylist.get(1).split(" ")[1]);

        Boolean chkflg = false;
        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        }
        System.out.println(chkflg ? "OK" : "NG");

    }

} public class Main {

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

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        int k = Integer.valueOf(mylist.get(0));
        int a = Integer.valueOf(mylist.get(1).split(" ")[0]);
        int b = Integer.valueOf(mylist.get(1).split(" ")[1]);

        Boolean chkflg = false;
        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        }
        System.out.println(chkflg ? "OK" : "NG");

    }

} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Main {

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

        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader reader = new BufferedReader(is);

        List<String> mylist = new ArrayList<>();

        // 標準入力からの値を変数strinputに代入
        String strinput = reader.readLine();

        while (strinput != null) {

            mylist.add(strinput);
            strinput = reader.readLine();

        }

        int k = Integer.valueOf(mylist.get(0));
        int a = Integer.valueOf(mylist.get(1).split(" ")[0]);
        int b = Integer.valueOf(mylist.get(1).split(" ")[1]);

        Boolean chkflg = false;
        for (int i = a; i <= b; i++) {
            if (i % k == 0) {
                chkflg = true;
                break;
            }
        }
        System.out.println(chkflg ? "OK" : "NG");

    }

}
