import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int K = s.nextInt();
        int A = s.nextInt();
        int B = s.nextInt();

        double A_div = A / K;
        double B_div = B / K;

        if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
        s.close();
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int K = s.nextInt();
        int A = s.nextInt();
        int B = s.nextInt();

        double A_div = A / K;
        double B_div = B / K;

        if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
        s.close();
    }
} Main public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int K = s.nextInt();
        int A = s.nextInt();
        int B = s.nextInt();

        double A_div = A / K;
        double B_div = B / K;

        if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
        s.close();
    } main {
        Scanner s = new Scanner(System.in);
        int K = s.nextInt();
        int A = s.nextInt();
        int B = s.nextInt();

        double A_div = A / K;
        double B_div = B / K;

        if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
        s.close();
    } Scanner s = new Scanner(System.in); s new Scanner(System.in) int K = s.nextInt(); K s.nextInt() s.nextInt s int A = s.nextInt(); A s.nextInt() s.nextInt s int B = s.nextInt(); B s.nextInt() s.nextInt s double A_div = A / K; A_div A / K A K double B_div = B / K; B_div B / K B K if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        } B_div - A_div >= 1 || A % K == 0 || B % K == 0 B_div - A_div >= 1 || A % K == 0 || B % K == 0 B_div - A_div >= 1 B_div - A_div B_div A_div 1 A % K == 0 A % K A K 0 B % K == 0 B % K B K 0 {
            System.out.println("OK");
        } System.out.println("OK") System.out.println System.out System System.out "OK" {
            System.out.println("NG");
        } System.out.println("NG") System.out.println System.out System System.out "NG" s.close() s.close s String[] args args public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int K = s.nextInt();
        int A = s.nextInt();
        int B = s.nextInt();

        double A_div = A / K;
        double B_div = B / K;

        if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
        s.close();
    }
} public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int K = s.nextInt();
        int A = s.nextInt();
        int B = s.nextInt();

        double A_div = A / K;
        double B_div = B / K;

        if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
        s.close();
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int K = s.nextInt();
        int A = s.nextInt();
        int B = s.nextInt();

        double A_div = A / K;
        double B_div = B / K;

        if (B_div - A_div >= 1 || A % K == 0 || B % K == 0) {
            System.out.println("OK");
        } else {
            System.out.println("NG");
        }
        s.close();
    }
}