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)

//   PIGMEISTER™   //

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define sidha(i,x,n) for(ll i=(ll)(x);i<(ll)(n);++i)
#define ulta(i,x,n) for(ll i=(ll)(x);i>=(ll)(n);--i)
#define sab(a) a.begin(),a.end()
#define bas(a) a.rbegin(),a.rend()
#define test ll _;cin>>_;while(_--)
#define jaldi ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define MOD (ll)1000000007
//#define MOD (ll)998244353
#define MAX 100005

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

    if ((a-1)/k != b/k) cout << "OK\n";
    else cout << "NG\n";
    
    return 0;
}