import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        int k = Integer.parseInt(br.readLine());
        
        String[] input = br.readLine().split(" ");
        int a = Integer.parseInt(input[0]);
        int b = Integer.parseInt(input[1]);
        
        String ans = "NG";
        
        for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        }
        
        out.println(ans);
        
        out.close();
        
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        int k = Integer.parseInt(br.readLine());
        
        String[] input = br.readLine().split(" ");
        int a = Integer.parseInt(input[0]);
        int b = Integer.parseInt(input[1]);
        
        String ans = "NG";
        
        for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        }
        
        out.println(ans);
        
        out.close();
        
    }
} Main public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        int k = Integer.parseInt(br.readLine());
        
        String[] input = br.readLine().split(" ");
        int a = Integer.parseInt(input[0]);
        int b = Integer.parseInt(input[1]);
        
        String ans = "NG";
        
        for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        }
        
        out.println(ans);
        
        out.close();
        
    } main {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        int k = Integer.parseInt(br.readLine());
        
        String[] input = br.readLine().split(" ");
        int a = Integer.parseInt(input[0]);
        int b = Integer.parseInt(input[1]);
        
        String ans = "NG";
        
        for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        }
        
        out.println(ans);
        
        out.close();
        
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out)); out new PrintWriter(new OutputStreamWriter(System.out)) int k = Integer.parseInt(br.readLine()); k Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br String[] input = br.readLine().split(" "); input br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int a = Integer.parseInt(input[0]); a Integer.parseInt(input[0]) Integer.parseInt Integer input[0] input 0 int b = Integer.parseInt(input[1]); b Integer.parseInt(input[1]) Integer.parseInt Integer input[1] input 1 String ans = "NG"; ans "NG" for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        } int i = a; int i = a; i a i <= b i b i++ i++ i {
            if(i % k == 0){
                ans = "OK";
                break;
            }
        } {
            if(i % k == 0){
                ans = "OK";
                break;
            }
        } if(i % k == 0){
                ans = "OK";
                break;
            } i % k == 0 i % k i k 0 {
                ans = "OK";
                break;
            } ans = "OK" ans "OK" break; out.println(ans) out.println out ans out.close() out.close out String[] args args public class Main {
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        int k = Integer.parseInt(br.readLine());
        
        String[] input = br.readLine().split(" ");
        int a = Integer.parseInt(input[0]);
        int b = Integer.parseInt(input[1]);
        
        String ans = "NG";
        
        for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        }
        
        out.println(ans);
        
        out.close();
        
    }
} public class Main {
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        int k = Integer.parseInt(br.readLine());
        
        String[] input = br.readLine().split(" ");
        int a = Integer.parseInt(input[0]);
        int b = Integer.parseInt(input[1]);
        
        String ans = "NG";
        
        for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        }
        
        out.println(ans);
        
        out.close();
        
    }
} Main
import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
        
        int k = Integer.parseInt(br.readLine());
        
        String[] input = br.readLine().split(" ");
        int a = Integer.parseInt(input[0]);
        int b = Integer.parseInt(input[1]);
        
        String ans = "NG";
        
        for(int i = a; i <= b; i++){
            if(i % k == 0){
                ans = "OK";
                break;
            }
        }
        
        out.println(ans);
        
        out.close();
        
    }
}