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;

void solve()
{
	int k, a, b;
	cin >> k >> a >> b;
	
	int p = a / k;
	p *= k;
	
	if(p < a)
		p += k;
	
	if(p <= b)
	{
		cout << "OK\n";
	}
	else
	{
		cout << "NG\n";
	}
}

main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t = 1;

//	cin >> t;

	for(; t; --t)
	{
		solve();
	}
}