#include <bits/stdc++.h> 
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
#include<cmath>
#define pb push_back
#define ll long long
#define ull unsigned long long
#define deb(x) cerr<<#x<<" "<<x<<"\n"
#define debi cerr<<"hey sparky\n"
#define x first
#define y second
#define fast ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define newline cout<<"\n"
#define yes cout<<"OK"<<"\n"
#define no cout<<"NG"<<"\n"
#define INF (ll)1e14+5
#define nax (ll)5e4+3
#define eps (double)1e-9
#define all(x) x.begin(),x.end()
#define MAX_N 3005
using namespace std;
using namespace __gnu_pbds; 
typedef tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> pdbs;
// look for  all edge cases
//search for a pattern




int main(){
	fast;
	int t;
	int a,b,k;
	cin >> k >> a >> b;
	a = a/k;
	b = b/k;
	if(a!=b || a%k == 0 || b%k == 0){
		yes;
	}
	else{
		no;
	}
 	
	return 0;
}

	
