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>
#define lli long long int
#define uli unsigned long long int
#define rep(i, m, n) for (lli i = m; i < (n); i++)
#define repe(i, m, n) for (lli i = m; i <= (n); i++)
#define ALL(x) (x).begin(), (x).end()
#define SIZE(x) ((lli)(x).size())
#define MAX(x) *max_element(ALL(x))
#define INF 1000000000000 //10^12
#define MOD 10000007      //10^9+7
#define SORT(n) sort(n.begin(), n.end())
#define SORTR(n) sort(n.begin(), n.end(), greater<int>())
#define REV(n) reverse(n.begin(), n.end())
#define Vec(K, L, N, S) vector<L> K(N, S)
#define rt sqrt
using namespace std;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vlli = vector<lli>;
using vs = vector<string>;
using ll = long long;
// vector入力
template <typename T>
istream &operator>>(istream &is, vector<T> &vec)
{
  for (T &x : vec)
    is >> x;
  return is;
}
// vector出力
template <typename T>
ostream &operator<<(ostream &os, vector<T> &vec)
{
  // os << '{';
  for (int i = 0; i < vec.size(); i++)
  {
    os << vec[i] << (i + 1 == vec.size() ? "" : "");
  }
  // os << '}';
  return os;
}

int main()
{
  ios::sync_with_stdio(false);
  cin.tie(0);
  lli a, b, c, h, k, n, w, ans = 0, count = 0;
  string s, t;
  cin >> k;
  cin >> a >> b;
  repe(i, a, b)
  {
    if (i % k == 0)
    {
      count++;
    }
  }
  if (count > 0)
  {
    cout << "OK" << endl;
  }
  else
  {
    cout << "NG" << endl;
  }
}