Problem:
Score: 100 points

Problem Statement

Takahashi the Jumbo will practice golf.

His objective is to get a carry distance that is a multiple of K, while he can only make a carry distance of between A and B (inclusive).

If he can achieve the objective, print OK; if he cannot, print NG.

Constraints

All values in input are integers.

1 \leq A \leq B \leq 1000

1 \leq K \leq 1000

Input

Input is given from Standard Input in the following format:

K
A B

Output

If he can achieve the objective, print OK; if he cannot, print NG.

Sample Input 1

7
500 600

Sample Output 1

OK

Among the multiples of 7, for example, 567 lies between 500 and 600.

Sample Input 2

4
5 7

Sample Output 2

NG

No multiple of 4 lies between 5 and 7.

Sample Input 3

1
11 11

Sample Output 3

OK

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.io.*;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
    /*public static StreamTokenizer in;
    static {
        try{
            in = new StreamTokenizer(new BufferedReader(new InputStreamReader(new BufferedInputStream(System.in))));
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    public static int nextInt() throws IOException{ in.nextToken(); return (int)in.nval; }*/
    public static void main(String[] args) throws IOException{
        Scanner sc=new Scanner(new BufferedInputStream(System.in));
        int a=sc.nextInt();
        int b=sc.nextInt();
        int c=sc.nextInt();
        int d=b/a*a;
        if(b%a!=0)
            d+=a;
        if(c>=d)
            System.out.println("OK");
        else System.out.println("NG");
    }
}