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<math.h>
#include<vector>
#include<array>
#include<algorithm>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
#include<deque>
#include<set>
#include<cstdio>
#include<cstring>
#include<string>
using namespace std;
using ll = long long;
using P = pair<int, int>;
const ll INF=1e18;
#define PI 3.14159265358979323846
const int MAX = 510000;
const int MOD = 1000000007;

ll fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

// 二項係数計算
ll COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

int pickUpNumbersFromStr(string S, int first, int second) {
    string strResult = S.substr(first-1, second - first + 1);
    return atoi(strResult.c_str());
}

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

    int K, S, L;
    cin >> K >> S >> L;
    for (int i=S; i<=L; i++) {
        if (i % K == 0) {
            cout << "OK" << '\n';
            return 0;
        }
    } 

    cout << "NG" << '\n';

    return 0;
}