import java.util.Scanner;

public class Main {
    public static void main(String[] arg) {
        Scanner scan = new Scanner(System.in);

        int factor = scan.nextInt();
        int minDist = scan.nextInt();
        int maxDist = scan.nextInt();

        for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        }
        System.out.println("NG");
        scan.close();
        return;
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] arg) {
        Scanner scan = new Scanner(System.in);

        int factor = scan.nextInt();
        int minDist = scan.nextInt();
        int maxDist = scan.nextInt();

        for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        }
        System.out.println("NG");
        scan.close();
        return;
    }
} Main public static void main(String[] arg) {
        Scanner scan = new Scanner(System.in);

        int factor = scan.nextInt();
        int minDist = scan.nextInt();
        int maxDist = scan.nextInt();

        for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        }
        System.out.println("NG");
        scan.close();
        return;
    } main {
        Scanner scan = new Scanner(System.in);

        int factor = scan.nextInt();
        int minDist = scan.nextInt();
        int maxDist = scan.nextInt();

        for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        }
        System.out.println("NG");
        scan.close();
        return;
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int factor = scan.nextInt(); factor scan.nextInt() scan.nextInt scan int minDist = scan.nextInt(); minDist scan.nextInt() scan.nextInt scan int maxDist = scan.nextInt(); maxDist scan.nextInt() scan.nextInt scan for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        } int i = minDist; int i = minDist; i minDist i <= maxDist i maxDist ++i ++i i {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        } {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        } if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            } i % factor == 0 i % factor i factor 0 {
                System.out.println("OK");
                scan.close();
                return;
            } System.out.println("OK") System.out.println System.out System System.out "OK" scan.close() scan.close scan return; System.out.println("NG") System.out.println System.out System System.out "NG" scan.close() scan.close scan return; String[] arg arg public class Main {
    public static void main(String[] arg) {
        Scanner scan = new Scanner(System.in);

        int factor = scan.nextInt();
        int minDist = scan.nextInt();
        int maxDist = scan.nextInt();

        for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        }
        System.out.println("NG");
        scan.close();
        return;
    }
} public class Main {
    public static void main(String[] arg) {
        Scanner scan = new Scanner(System.in);

        int factor = scan.nextInt();
        int minDist = scan.nextInt();
        int maxDist = scan.nextInt();

        for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        }
        System.out.println("NG");
        scan.close();
        return;
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] arg) {
        Scanner scan = new Scanner(System.in);

        int factor = scan.nextInt();
        int minDist = scan.nextInt();
        int maxDist = scan.nextInt();

        for(int i = minDist; i <= maxDist; ++i) {
            if(i % factor == 0) {
                System.out.println("OK");
                scan.close();
                return;
            }
        }
        System.out.println("NG");
        scan.close();
        return;
    }
}