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>
typedef long long ll;
#define rep(i,a,n) for(ll i = a;i < n;i++)
#define rrep(i,a,n) for(ll i = n; i >= a;i--)
#define LINF 1e18
#define INF 1e9
using namespace std;

int main(){
    ll a,b,k;
    cin >> k >> a >> b;

    rep(i,a,b+1){
        if(i % k == 0){
            cout << "OK" << endl;
            return 0;
        }
    }
    cout << "NG" << endl;
    return 0;
}