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;
#define REP(i, n) for(int i=0, i##_len=(n); i<i##_len; ++i)
typedef long long ll;
#define pb push_back
#define fi first
#define se second
#define ALL(x) (x).begin(),(x).end()
#define RALL(x) (x).rbegin(),(x).rend()
template <class T, class U> ostream &operator<<(ostream &os, const pair<T, U> &p){os<<"("<<p.first<<","<< p.second<<")";return os;}
template <class T> ostream &operator<<(ostream &os, const vector<T> &v){os<<"{";REP(i,(int)v.size()){if(i)os<<",";os<<v[i];}os<<"}";return os;}
template <typename T, size_t S> void printArray(const T (&array)[S]){for(auto val : array)std::cout << val << ", ";std::cout << "\n";}
void Yes() {cout << "Yes" << endl;}
void No() {cout << "No" << endl;}
void YES() {cout << "YES" << endl;}
void NO() {cout << "NO" << endl;}
const double PI=acos(-1);
const ll MOD = 1000000007;
using Graph = vector<vector<int>>;
//const int dx[4] = {1, 0, -1, 0};
//const int dy[4] = {0, 1, 0, -1};
//const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
//const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};

void solve(){
    ll k; cin >> k;
    ll a, b; cin >> a>> b;
    bool flag = false;
    for(ll i=a; i<=b; i++){
        if(i%k==0) flag = true;
    }
    if(flag) cout << "OK" << endl;
    else cout << "NG" << endl;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    solve();
}