import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        }
    }

    private static boolean can(int k, int a, int b) {
        for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        }
        return false;
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        }
    }

    private static boolean can(int k, int a, int b) {
        for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        }
        return false;
    }
} Main public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        }
    } main {
        try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        }
    } try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        } {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        } Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) int K = sc.nextInt(); K sc.nextInt() sc.nextInt sc int A = sc.nextInt(); A sc.nextInt() sc.nextInt sc int B = sc.nextInt(); B sc.nextInt() sc.nextInt sc System.out.println(can(K, A, B) ? "OK" : "NG") System.out.println System.out System System.out can(K, A, B) ? "OK" : "NG" can(K, A, B) can K A B "OK" "NG" String[] args args private static boolean can(int k, int a, int b) {
        for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        }
        return false;
    } can {
        for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        }
        return false;
    } for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        } int n = 1; int n = 1; n 1 n * k <= b n * k n k b n++ n++ n {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        } {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        } if (n * k >= a && n * k <= b) {
                return true;
            } n * k >= a && n * k <= b n * k >= a n * k n k a n * k <= b n * k n k b {
                return true;
            } return true; true return false; false int k k int a a int b b public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        }
    }

    private static boolean can(int k, int a, int b) {
        for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        }
        return false;
    }
} public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        }
    }

    private static boolean can(int k, int a, int b) {
        for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        }
        return false;
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            int K = sc.nextInt();
            int A = sc.nextInt();
            int B = sc.nextInt();
            System.out.println(can(K, A, B) ? "OK" : "NG");
        }
    }

    private static boolean can(int k, int a, int b) {
        for (int n = 1; n * k <= b; n++) {
            if (n * k >= a && n * k <= b) {
                return true;
            }
        }
        return false;
    }
}
