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 <bits/stdc++.h>
#include <cassert>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
using Graph = vector<vector<int>>;

const long long MOD = 1000000007;
const long long INF = 1LL << 60;
const int INT_INF = 1000000000;

// int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int dx[8] = {-1, -1, -1, 0, 0, 1, 1, 1}, dy[8] = {-1, 0, 1, 1, -1, 1, 0, -1};

int main()
{
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int K, A, B;
  cin >> K >> A >> B;
  bool can = false;
  for (int i = A; i <= B; i++)
  {
    if (i % K == 0)
      can = true;
  }
  if (can)
    cout << "OK" << endl;
  else
    cout << "NG" << endl;
  return 0;
}