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 C++ (GCC 9.2.1) (judge verdict: Accepted)

#include <math.h>
#include <iostream>
#include <string>
using namespace std;
int main(void){
  bool check = false;
  int k, a, b;
  cin >> k;
  cin >> a;
  cin >> b;
  while((check == false) && (a <= b)){
    if((a % k) == 0){
      check = true;
      cout << "OK" << endl;
    }
    a++;
  }
  if(check == false){
    cout << "NG" << endl;
  }
  return 0;
}