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++ (Clang 10.0.0) (judge verdict: Accepted)

//
//  main.cpp
//

#include <algorithm>
#include <array>
#include <assert.h>
#include <complex>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <math.h>
#include <memory>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

using ll = int64_t;
using ull = uint64_t;

[[maybe_unused]] constexpr ll LL_MAX = numeric_limits<ll>::max();
[[maybe_unused]] constexpr ll LL_MIN = numeric_limits<ll>::min();
[[maybe_unused]] constexpr ull ULL_MAX = numeric_limits<ull>::max();

#define rep(i, a, b) for (ll i = (a); i < (b); i++)
#define rrep(i, a, b) for (ll i = (a)-1; i >= (b); i--)

template <typename T>
void chmin(T& x, T y) {
    x = min(x, y);
}

template <typename T>
void chmax(T& x, T y) {
    x = max(x, y);
}

ll csum(ll x, ll y) {
    if (x > 0 && y > 0 && x > LL_MAX - y) {
        return LL_MAX;
    }
    if (x < 0 && y < 0 && x < LL_MIN - y) {
        return LL_MIN;
    }
    return x + y;
}

template<typename T>
vector<T> make_vec_nd(T init, ll size) {
	return vector<T>(size, init);
}
template<typename T, typename... Args>
auto make_vec_nd(T init, ll size, Args... rest) {
	auto inner = make_vec_nd(init, rest...);
	return vector<decltype(inner)>(size, inner);
}

int main() {
    ll K;
    cin >> K;
    ll A, B;
    cin >> A >> B;
    rep(i,A,B+1) {
        if (i % K == 0) {
            cout << "OK" << endl;
            return 0;
        }
    }
    cout << "NG" << endl;
}