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();

        boolean trueCount = false;
        for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        }
        System.out.println(trueCount == true ? "OK" : "NG");
    }
} 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();

        boolean trueCount = false;
        for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        }
        System.out.println(trueCount == true ? "OK" : "NG");
    }
} 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();

        boolean trueCount = false;
        for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        }
        System.out.println(trueCount == true ? "OK" : "NG");
    } main {
        Scanner sc = new Scanner(System.in);

        int K = sc.nextInt();
        int A = sc.nextInt();
        int B = sc.nextInt();

        boolean trueCount = false;
        for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        }
        System.out.println(trueCount == true ? "OK" : "NG");
    } 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 boolean trueCount = false; trueCount false for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        } int i = A; int i = A; i A i<=B i B i++ i++ i {
            if(i % K == 0){
                trueCount = true;
            }
        } {
            if(i % K == 0){
                trueCount = true;
            }
        } if(i % K == 0){
                trueCount = true;
            } i % K == 0 i % K i K 0 {
                trueCount = true;
            } trueCount = true trueCount true System.out.println(trueCount == true ? "OK" : "NG") System.out.println System.out System System.out trueCount == true ? "OK" : "NG" trueCount == true trueCount true "OK" "NG" 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();

        boolean trueCount = false;
        for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        }
        System.out.println(trueCount == true ? "OK" : "NG");
    }
} 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();

        boolean trueCount = false;
        for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        }
        System.out.println(trueCount == true ? "OK" : "NG");
    }
} 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();

        boolean trueCount = false;
        for(int i = A; i<=B; i++){
            if(i % K == 0){
                trueCount = true;
            }
        }
        System.out.println(trueCount == true ? "OK" : "NG");
    }
}