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>

#ifdef DEBUG
#define debug(x) cout << #x << ": " << x << endl
#else
#define debug(x)
#endif

#define REP(i, n) for(int i = 0; i < (n); i++)
#define REPS(i, n) for(int i = 1; i <= (n); i++)
#define ALL(v) (v).begin(), (v).end()

#define pb push_back
#define mp make_pair
#define mt make_tuple

using namespace std;

using ll = long long;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
using vs = vector<string>;

const ll INF = 1e18;
const ll MOD = 1e9+7;

template<class T> inline bool chmax(T &a, const T &b) { if (a<b) { a = b; return true;} return false; }
template<class T> inline bool chmin(T &a, const T &b) { if (a>b) { a = b; return true;} return false; }

signed main()
{
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    int K, A, B; cin >> K >> A >> B;
    for(int i = A; i <= B; i++)
    {
        if(i % K == 0)
        {
            cout << "OK" << endl;
            return 0;
        }
    }
    cout << "NG" << endl;
}