import java.util.Scanner;
 
public class Main{
 
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
		System.out.print(" ");
 
		int K = scanner.nextInt();
		int A = scanner.nextInt();
		int B = scanner.nextInt();
 
		int largest = (B / K) * K;
		
		if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		}
		scanner.close();
     
	}
} import java.util.Scanner; Scanner java.util public class Main{
 
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
		System.out.print(" ");
 
		int K = scanner.nextInt();
		int A = scanner.nextInt();
		int B = scanner.nextInt();
 
		int largest = (B / K) * K;
		
		if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		}
		scanner.close();
     
	}
} Main public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
		System.out.print(" ");
 
		int K = scanner.nextInt();
		int A = scanner.nextInt();
		int B = scanner.nextInt();
 
		int largest = (B / K) * K;
		
		if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		}
		scanner.close();
     
	} main {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
		System.out.print(" ");
 
		int K = scanner.nextInt();
		int A = scanner.nextInt();
		int B = scanner.nextInt();
 
		int largest = (B / K) * K;
		
		if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		}
		scanner.close();
     
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) System.out.print(" ") System.out.print System.out System System.out " " int K = scanner.nextInt(); K scanner.nextInt() scanner.nextInt scanner int A = scanner.nextInt(); A scanner.nextInt() scanner.nextInt scanner int B = scanner.nextInt(); B scanner.nextInt() scanner.nextInt scanner int largest = (B / K) * K; largest (B / K) * K (B / K) B K K if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		} A <= largest A largest {
			System.out.println("OK");
		} System.out.println("OK") System.out.println System.out System System.out "OK" {
			System.out.println("NG");
		} System.out.println("NG") System.out.println System.out System System.out "NG" scanner.close() scanner.close scanner String[] args args public class Main{
 
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
		System.out.print(" ");
 
		int K = scanner.nextInt();
		int A = scanner.nextInt();
		int B = scanner.nextInt();
 
		int largest = (B / K) * K;
		
		if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		}
		scanner.close();
     
	}
} public class Main{
 
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
		System.out.print(" ");
 
		int K = scanner.nextInt();
		int A = scanner.nextInt();
		int B = scanner.nextInt();
 
		int largest = (B / K) * K;
		
		if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		}
		scanner.close();
     
	}
} Main
import java.util.Scanner;
 
public class Main{
 
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
		System.out.print(" ");
 
		int K = scanner.nextInt();
		int A = scanner.nextInt();
		int B = scanner.nextInt();
 
		int largest = (B / K) * K;
		
		if (A <= largest) {
			System.out.println("OK");
		} else {
			System.out.println("NG");
		}
		scanner.close();
     
	}
}