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>
using namespace std;

#define rep(i, n) for(long long i=0;i<(long long)(n);i++)
#define rep2(i, s, n) for(long long i=(s);i<(long long)(n);i++)
#define all(v) v.begin(), v.end()

using ll = long long;
using vll = vector<ll>;
using vvll = vector<vll>;

const ll INF = (1LL<<60);

int main(){

    ll k, a, b; cin >> k >> a >> b;

    for(ll i=a;i<=b;i++){
        if(i%k==0){
            cout << "OK" << endl;
            return 0;
        }
    }

    cout << "NG" << endl;

    return 0;
}