import java.util.Scanner;
class Main{
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        int low = scan.nextInt();
        int high = scan.nextInt();
        int i;
        int a = 0;
        for( i = 1;i < 1000; i ++){
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        }
        if(low <= a && a <= high){
            System.out.println("OK");
        }else{
            System.out.println("NG");
        }
    }

} import java.util.Scanner; Scanner java.util class Main{
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        int low = scan.nextInt();
        int high = scan.nextInt();
        int i;
        int a = 0;
        for( i = 1;i < 1000; i ++){
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        }
        if(low <= a && a <= high){
            System.out.println("OK");
        }else{
            System.out.println("NG");
        }
    }

} Main public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        int low = scan.nextInt();
        int high = scan.nextInt();
        int i;
        int a = 0;
        for( i = 1;i < 1000; i ++){
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        }
        if(low <= a && a <= high){
            System.out.println("OK");
        }else{
            System.out.println("NG");
        }
    } main {
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        int low = scan.nextInt();
        int high = scan.nextInt();
        int i;
        int a = 0;
        for( i = 1;i < 1000; i ++){
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        }
        if(low <= a && a <= high){
            System.out.println("OK");
        }else{
            System.out.println("NG");
        }
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int num = scan.nextInt(); num scan.nextInt() scan.nextInt scan int low = scan.nextInt(); low scan.nextInt() scan.nextInt scan int high = scan.nextInt(); high scan.nextInt() scan.nextInt scan int i; i int a = 0; a 0 for( i = 1;i < 1000; i ++){
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        } i = 1; i = 1 i 1 i < 1000 i 1000 i ++ i ++ i {
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        } {
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        } a = num * i a num * i num i if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            } low <= a && a <= high low <= a low a a <= high a high {
                //System.out.println("OK");
                //System.out.println(i);
                break;
            } break; if(low <= a && a <= high){
            System.out.println("OK");
        }else{
            System.out.println("NG");
        } low <= a && a <= high low <= a low a a <= high a high {
            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" String args[] args
import java.util.Scanner;
class Main{
    public static void main(String args[]){
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        int low = scan.nextInt();
        int high = scan.nextInt();
        int i;
        int a = 0;
        for( i = 1;i < 1000; i ++){
            a = num * i;
            if(low <= a && a <= high ){
                //System.out.println("OK");
                //System.out.println(i);
                break;
            }
        }
        if(low <= a && a <= high){
            System.out.println("OK");
        }else{
            System.out.println("NG");
        }
    }

}