 import java.util.*;

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

        Scanner sc = new Scanner(System.in);
        int k = Integer.parseInt(sc.next());
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        String ans = "NG";
        for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        }

        System.out.println(ans);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int k = Integer.parseInt(sc.next());
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        String ans = "NG";
        for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        }

        System.out.println(ans);
    }
} Main public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int k = Integer.parseInt(sc.next());
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        String ans = "NG";
        for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        }

        System.out.println(ans);
    } main {

        Scanner sc = new Scanner(System.in);
        int k = Integer.parseInt(sc.next());
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        String ans = "NG";
        for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        }

        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int k = Integer.parseInt(sc.next()); k Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int a = Integer.parseInt(sc.next()); a Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int b = Integer.parseInt(sc.next()); b Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc String ans = "NG"; ans "NG" for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        } int i = a; int i = a; i a i < b + 1 i b + 1 b 1 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) {

        Scanner sc = new Scanner(System.in);
        int k = Integer.parseInt(sc.next());
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        String ans = "NG";
        for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        }

        System.out.println(ans);
    }
} public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int k = Integer.parseInt(sc.next());
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        String ans = "NG";
        for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        }

        System.out.println(ans);
    }
} Main
 import java.util.*;

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

        Scanner sc = new Scanner(System.in);
        int k = Integer.parseInt(sc.next());
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        String ans = "NG";
        for (int i = a; i < b + 1; i++) {
            if (i % k == 0) {
                ans = "OK";
                break;
            }
        }

        System.out.println(ans);
    }
}
