import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

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

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