import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        int k = Integer.parseInt(str);
        String[] cov = lines[1].split(" ");
        int a = Integer.parseInt(cov[0]);
        int b = Integer.parseInt(cov[1]);
        int c = b - a;
        
            for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            }
            System.out.println("NG");
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        int k = Integer.parseInt(str);
        String[] cov = lines[1].split(" ");
        int a = Integer.parseInt(cov[0]);
        int b = Integer.parseInt(cov[1]);
        int c = b - a;
        
            for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            }
            System.out.println("NG");
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} Main public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        int k = Integer.parseInt(str);
        String[] cov = lines[1].split(" ");
        int a = Integer.parseInt(cov[0]);
        int b = Integer.parseInt(cov[1]);
        int c = b - a;
        
            for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            }
            System.out.println("NG");
   } main {
        String[] lines = getStdin();
        String str = lines[0];
        int k = Integer.parseInt(str);
        String[] cov = lines[1].split(" ");
        int a = Integer.parseInt(cov[0]);
        int b = Integer.parseInt(cov[1]);
        int c = b - a;
        
            for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            }
            System.out.println("NG");
   } String[] lines = getStdin(); lines getStdin() getStdin String str = lines[0]; str lines[0] lines 0 int k = Integer.parseInt(str); k Integer.parseInt(str) Integer.parseInt Integer str String[] cov = lines[1].split(" "); cov lines[1].split(" ") lines[1].split lines[1] lines 1 " " int a = Integer.parseInt(cov[0]); a Integer.parseInt(cov[0]) Integer.parseInt Integer cov[0] cov 0 int b = Integer.parseInt(cov[1]); b Integer.parseInt(cov[1]) Integer.parseInt Integer cov[1] cov 1 int c = b - a; c b - a b a for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            } int i = a; int i = a; i a i <= b i b i++ i++ i {
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            } {
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            } if (i % k == 0){
                    System.out.println("OK");
                    return;
                } i % k == 0 i % k i k 0 {
                    System.out.println("OK");
                    return;
                } System.out.println("OK") System.out.println System.out System System.out "OK" return; System.out.println("NG") System.out.println System.out System System.out "NG" String[] args args private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  } getStdin {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) ArrayList<String> lines = new ArrayList<>(); lines new ArrayList<>() while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    } scanner.hasNext() scanner.hasNext scanner {
      lines.add(scanner.nextLine());
    } lines.add(scanner.nextLine()) lines.add lines scanner.nextLine() scanner.nextLine scanner return lines.toArray(new String[lines.size()]); lines.toArray(new String[lines.size()]) lines.toArray lines new String[lines.size()] lines.size() lines.size lines public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        int k = Integer.parseInt(str);
        String[] cov = lines[1].split(" ");
        int a = Integer.parseInt(cov[0]);
        int b = Integer.parseInt(cov[1]);
        int c = b - a;
        
            for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            }
            System.out.println("NG");
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        int k = Integer.parseInt(str);
        String[] cov = lines[1].split(" ");
        int a = Integer.parseInt(cov[0]);
        int b = Integer.parseInt(cov[1]);
        int c = b - a;
        
            for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            }
            System.out.println("NG");
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} Main
import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String str = lines[0];
        int k = Integer.parseInt(str);
        String[] cov = lines[1].split(" ");
        int a = Integer.parseInt(cov[0]);
        int b = Integer.parseInt(cov[1]);
        int c = b - a;
        
            for(int i = a; i <= b; i++){
                if (i % k == 0){
                    System.out.println("OK");
                    return;
                }
            }
            System.out.println("NG");
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
}