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 <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <bitset>
#include <iomanip>
#include <climits>
using namespace std;
typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<string> VS;
typedef vector< vector<int> > VVI;
typedef vector< vector<ll> > VVL;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
#define rep(i,n) for(ll i=0;i<(n);i++)
#define all(a) (a).begin(),(a).end()
#define pf push_front
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define ub upper_bound
#define lb lower_bound

int main(){
  int K,A,B;
  cin>>K>>A>>B;
  int ans=0;
  rep(i,10000){
    if(i>=A and i<=B){
      if(i%K==0) ans=1;
    }
  }
  if(ans) cout<<"OK"<<endl;
  else cout<<"NG"<<endl;
}