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)

// @prefix atcoder
// @description atcoder template

#include <bits/stdc++.h>
using namespace std;
#define int long long

// typedef
//------------------------------------------
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef vector<PII> VP;

// rep
//------------------------------------------
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) (x).begin(), (x).end()
#define DEBUG(x) cerr << #x << ": " << x << '\n'
#define DEBUGP(x) cerr << #x << ": " << x.first << " \t" << x.second << '\n'

int k;
int a, b;

signed main() {
    cin >> k >> a >> b;

    REP(i, 10000) {
        int f = k * i;
        if (a <= f && f <= b) {
            cout << "OK" << endl;
            return 0;
        }
    }

    cout << "NG" << endl;
    return 0;
}