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 <iostream>
#include <vector>
#include <cassert>
#include <algorithm>
#include <functional>
#include <string>


using namespace std;
using ll = long long;
using P = pair<int, int>;

void view(const vector<int>& v) {
	for (size_t i = 0; i < v.size(); i++) {
		cout << v[i] << " ";
	}
	cout << endl;
}
void view(const vector<vector<long long>>& vv) {
	for (size_t i = 0; i < vv.size(); i++) {
		for (size_t j = 0; j < vv[i].size()-1; j++) {
			cout << vv[i][j] << " ";
		}
		cout << vv[i][vv[i].size()-1];
		cout << endl;
	}
}

int main() {
	int k;
	int A, B;
	string str;
	cin >> k;
	cin >> A >> B;

	for (int i = A; i <= B; i++) {
		int x;
		x = i;
		if (x%k == 0) {
			str = "OK";
			goto a;
		}
	}
	str = "NG";
	
a:
	cout << str;
	return 0;
}