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 <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <cmath>
#include <map>
#include <set>
#include <numeric>

using namespace std;

typedef long long ll;
typedef long double ld;

#define sz(a) int((a).size())
#define forn(i, n) for (int i = 0; i < int(n); ++i)
#define fore(i, l, r) for (int i = int(l); i < int(r); ++i)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define file_name(a) (freopen(((string)(a) + ".in").c_str(),"r",stdin), freopen(((string)(a) + ".out").c_str(),"w",stdout))


int nxt() {
	int x;
	cin >> x;
	return x;
}

int main() {
	int k = nxt(), a = nxt(), b = nxt();
	for (int i = a; i <= b; i++) {
		if (i % k == 0) {
			cout << "OK\n";
			return 0;
		}
	}
	cout << "NG\n";
	return 0;
}