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: Wrong Answer)

#include<iostream>
#include<iomanip>
#include<algorithm>
#include<math.h>
#include<vector>
using namespace std;

int main() 
{
	int k;
	int a, b;
	cin >> k;
	cin >> a >> b;

	if (k == 1 || a % k == 0 || b % k == 0 || (a < k && k < b))
		cout << "OK";
	else if (a == b) 
	{
		if (a % k == 0)
			cout << "OK";
		else
			cout << "NG";
	}
	else
	{
		if(b - a >= k) 
			cout << "OK";
		else 
			cout << "NG";
	}
	return 0;
}