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)

/*
 * author :Sadik Hassan
 *
*/
#include "bits/stdc++.h"
using namespace std;
#define ll            long long
#define nl            "\n"
#define pb            push_back
#define fi            first
#define se            second
#define PI            (acos(-1.0))
#define _SAD()        ios::sync_with_stdio(0),cin.tie(0), cout.tie(0);
#define repp(i,a,n)   for(int i=a;i<n;i++)
#define rep(i,n)      for(int i=0;i<n;i++)
#define SZ(s)         s.size()
#define SRT(x,y)      sort(x,x+y)
#define REV(a,b)      reverse(a,a+b)
#define VSRT(x)       sort(x.begin(),x.end())
#define VREV(x)       reverse(x.begin(),x.end())
#define w(t)          int t;cin>>t;while(t--)
#define TSFL(s)       transform(s.begin(),s.end(),s.begin(),::toupper);
#define TSFH(s)       transform(s.begin(),s.end(),s.begin(),::tolower);
typedef vector<int> vi;
typedef vector<ll> vii;
typedef set<int> si;
typedef set<ll> sii;

const int N = 1e5+10;
const int INF = (int)1e9+5;

int main()
{
    _SAD()
    int a,b,k;
    cin>>a>>b>>k;
    for(int i=1;;i++)
    {
        if(i*k>=a&&i*k<=b)
        {
            cout<<"OK"<<nl;return 0;
        }
        if(i*k>b){cout<<"NG"<<nl;
        return 0;
    }
    }
    return 0;
}