import java.util.Scanner;

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

        int KA = A/K; int KB = B/K;

        if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        }

        sc.close();
    }
} import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int K = sc.nextInt();
        int A = sc.nextInt();
        int B = sc.nextInt();

        int KA = A/K; int KB = B/K;

        if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        }

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

        int KA = A/K; int KB = B/K;

        if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        }

        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        int K = sc.nextInt();
        int A = sc.nextInt();
        int B = sc.nextInt();

        int KA = A/K; int KB = B/K;

        if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        }

        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int K = sc.nextInt(); K sc.nextInt() sc.nextInt sc int A = sc.nextInt(); A sc.nextInt() sc.nextInt sc int B = sc.nextInt(); B sc.nextInt() sc.nextInt sc int KA = A/K; KA A/K A K int KB = B/K; KB B/K B K if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        } KA<KB KA KB {
            System.out.println("OK");
        } System.out.println("OK") System.out.println System.out System System.out "OK" if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        } A%K==0 A%K A K 0 {
            System.out.println("OK");
        } System.out.println("OK") System.out.println System.out System System.out "OK" if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        } 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" sc.close() sc.close sc String[] args args public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int K = sc.nextInt();
        int A = sc.nextInt();
        int B = sc.nextInt();

        int KA = A/K; int KB = B/K;

        if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        }

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

        int KA = A/K; int KB = B/K;

        if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        }

        sc.close();
    }
} Main
import java.util.Scanner;

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

        int KA = A/K; int KB = B/K;

        if(KA<KB){
            System.out.println("OK");
        } else if(A%K==0){
            System.out.println("OK");
        } else if(B%K==0){
            System.out.println("OK");
        } else{
            System.out.println("NG");
        }

        sc.close();
    }
}