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: Wrong Answer)

// template
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<long long, long long> LP;
#define INF 999999999
#define MOD 1000000007
#define REP(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define REP_AB(i, a, b) for (ll i = ll(a); i < ll(b); i++)
#define REP_IN(i, n, x) for (ll i = 0; i < n; i++)in>>x;
#define REP_OUT(i, n, x) for (ll i = 0; i < n; i++)out<<x<<endl;
#define ALL(v) v.begin(), v.end()
#define SORT(v) sort(ALL(v))
#define UNIQUE(v) sort(ALL(v));v.erase(unique(ALL(v)), v.end());
#define SIZE(x) ((ll)(x).size())
#define REVERSE(v) reverse(ALL(v))
// true / false
#define BIN_SEARCH(v, a) binary_search(ALL(v), a)
// index
#define BIN_LEFT(v, a) (lower_bound(ALL(v), a) - v.begin())
#define BIN_RIGHT(v, a) (upper_bound(ALL(v), a) - v.begin())
#define BIN_INSERT(v, a) (v.insert(v.begin() + BIN_LEFT(v, a), a))
#define DEL(v, i) v.erase(v.begin() + i)
#define INSERT(v, i, a) v.insert(v.begin() + i, a)
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return (a / gcd(a, b)) * b;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
#define out cout
#define in cin
#define endl '\n'
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
// template end
 
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    
    //vector<ll> X(N);
    //string s;
    //in >> s;
    //vector<string> s;
    //s.resize(N);
    ll N;
    in >> N;
    ll A,B;
    in >> A>>B;
    ll ans=0;
    

    if(B-A>=N || N==1){
        out << "OK" << endl; 
    }else{
        out << "NG" << endl; 
    }
    
    
    
}