import java.io.*;
public class Main{
    public static void main(String[] args) throws IOException{
        int K;
        String str;
        String[] A = new String[2];
        String ans = "NG";
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        K = Integer.parseInt(r.readLine());
        str = r.readLine();
        A = (str.split(" "));
        for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        }
        System.out.println(ans);
    }
} import java.io.*; io.* java public class Main{
    public static void main(String[] args) throws IOException{
        int K;
        String str;
        String[] A = new String[2];
        String ans = "NG";
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        K = Integer.parseInt(r.readLine());
        str = r.readLine();
        A = (str.split(" "));
        for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) throws IOException{
        int K;
        String str;
        String[] A = new String[2];
        String ans = "NG";
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        K = Integer.parseInt(r.readLine());
        str = r.readLine();
        A = (str.split(" "));
        for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        }
        System.out.println(ans);
    } main {
        int K;
        String str;
        String[] A = new String[2];
        String ans = "NG";
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        K = Integer.parseInt(r.readLine());
        str = r.readLine();
        A = (str.split(" "));
        for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        }
        System.out.println(ans);
    } int K; K String str; str String[] A = new String[2]; A new String[2] 2 String ans = "NG"; ans "NG" BufferedReader r = new BufferedReader(new InputStreamReader(System.in)); r new BufferedReader(new InputStreamReader(System.in)) K = Integer.parseInt(r.readLine()) K Integer.parseInt(r.readLine()) Integer.parseInt Integer r.readLine() r.readLine r str = r.readLine() str r.readLine() r.readLine r A = (str.split(" ")) A (str.split(" ")) str.split str " " for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        } int i=1; int i=1; i 1 i*K <= Integer.parseInt(A[1]) i*K i K Integer.parseInt(A[1]) Integer.parseInt Integer A[1] A 1 i++ i++ i {
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        } {
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        } if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            } Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1]) Integer.parseInt(A[0]) <= i*K Integer.parseInt(A[0]) Integer.parseInt Integer A[0] A 0 i*K i K i*K <= Integer.parseInt(A[1]) i*K i K Integer.parseInt(A[1]) Integer.parseInt Integer A[1] A 1 {
                ans="OK";
                continue;
            } ans="OK" ans "OK" continue; System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main{
    public static void main(String[] args) throws IOException{
        int K;
        String str;
        String[] A = new String[2];
        String ans = "NG";
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        K = Integer.parseInt(r.readLine());
        str = r.readLine();
        A = (str.split(" "));
        for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        }
        System.out.println(ans);
    }
} public class Main{
    public static void main(String[] args) throws IOException{
        int K;
        String str;
        String[] A = new String[2];
        String ans = "NG";
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        K = Integer.parseInt(r.readLine());
        str = r.readLine();
        A = (str.split(" "));
        for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        }
        System.out.println(ans);
    }
} Main
import java.io.*;
public class Main{
    public static void main(String[] args) throws IOException{
        int K;
        String str;
        String[] A = new String[2];
        String ans = "NG";
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        K = Integer.parseInt(r.readLine());
        str = r.readLine();
        A = (str.split(" "));
        for(int i=1;i*K <= Integer.parseInt(A[1]);i++){
            if(Integer.parseInt(A[0]) <= i*K && i*K <= Integer.parseInt(A[1])){
                ans="OK";
                continue;
            }
        }
        System.out.println(ans);
    }
}