#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>
#include <numeric>
#include <map>
typedef long long ll;
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;




int main() {
	int k,a,b;
	cin >> k>>a>>b;
	int x = b - a;
	if (k % x == 0) {
		cout << "NG" << endl;
	}
	else cout << "OK" << endl;


	return 0;
}