import java.util.*;

public class Main {
    public static void main (String[] args) {
        Scanner s = new Scanner(System.in);
          int number = Integer.parseInt(s.next());
        int min = Integer.parseInt(s.next());
        int max = Integer.parseInt(s.next());
          
          if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG");
      	
    }

    public static boolean flag (int max, int min, int number) {
        if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          }
    }
} import java.util.*; util.* java public class Main {
    public static void main (String[] args) {
        Scanner s = new Scanner(System.in);
          int number = Integer.parseInt(s.next());
        int min = Integer.parseInt(s.next());
        int max = Integer.parseInt(s.next());
          
          if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG");
      	
    }

    public static boolean flag (int max, int min, int number) {
        if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          }
    }
} Main public static void main (String[] args) {
        Scanner s = new Scanner(System.in);
          int number = Integer.parseInt(s.next());
        int min = Integer.parseInt(s.next());
        int max = Integer.parseInt(s.next());
          
          if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG");
      	
    } main {
        Scanner s = new Scanner(System.in);
          int number = Integer.parseInt(s.next());
        int min = Integer.parseInt(s.next());
        int max = Integer.parseInt(s.next());
          
          if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG");
      	
    } Scanner s = new Scanner(System.in); s new Scanner(System.in) int number = Integer.parseInt(s.next()); number Integer.parseInt(s.next()) Integer.parseInt Integer s.next() s.next s int min = Integer.parseInt(s.next()); min Integer.parseInt(s.next()) Integer.parseInt Integer s.next() s.next s int max = Integer.parseInt(s.next()); max Integer.parseInt(s.next()) Integer.parseInt Integer s.next() s.next s if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG"); flag(max, min, number) flag max min number System.out.println("OK") System.out.println System.out System System.out "OK" System.out.println("NG") System.out.println System.out System System.out "NG" String[] args args public static boolean flag (int max, int min, int number) {
        if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          }
    } flag {
        if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          }
    } if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          } (max - min) > number (max - min) max min number return true; true {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          } for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            } int i = min; int i = min; i min i <= max i max i++ i++ i {
                if (i%number == 0) {
                    return true;
                }
            } {
                if (i%number == 0) {
                    return true;
                }
            } if (i%number == 0) {
                    return true;
                } i%number == 0 i%number i number 0 {
                    return true;
                } return true; true return false; false int max max int min min int number number public class Main {
    public static void main (String[] args) {
        Scanner s = new Scanner(System.in);
          int number = Integer.parseInt(s.next());
        int min = Integer.parseInt(s.next());
        int max = Integer.parseInt(s.next());
          
          if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG");
      	
    }

    public static boolean flag (int max, int min, int number) {
        if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          }
    }
} public class Main {
    public static void main (String[] args) {
        Scanner s = new Scanner(System.in);
          int number = Integer.parseInt(s.next());
        int min = Integer.parseInt(s.next());
        int max = Integer.parseInt(s.next());
          
          if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG");
      	
    }

    public static boolean flag (int max, int min, int number) {
        if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          }
    }
} Main
import java.util.*;

public class Main {
    public static void main (String[] args) {
        Scanner s = new Scanner(System.in);
          int number = Integer.parseInt(s.next());
        int min = Integer.parseInt(s.next());
        int max = Integer.parseInt(s.next());
          
          if (flag(max, min, number)) System.out.println("OK");
          else System.out.println("NG");
      	
    }

    public static boolean flag (int max, int min, int number) {
        if ((max - min) > number) return true;
        else {
            for (int i = min; i <= max; i++) {
                if (i%number == 0) {
                    return true;
                }
            }
            return false;
          }
    }
}