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 forn(i,n) for(int i = 0; i < n; i++)
#define forr(i,a,n) for(int i = a; i<= n; i++)
#define __ ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define fi first
#define se second
#define pb push_back
#define all(u) u.begin(),u.end()
#define lli long long int
#define ld long double

using namespace std;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef vector<vi> vvi;
int a, b, k;
int main(){__
	cin >> k >> a >> b;
	forr(i,a,b){
		if(i % k == 0){
			cout << "OK\n";
			return 0;
		}
	}
	cout << "NG\n";
	return 0;
}