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 for(i,a,b) for(int i=(a);i<=(b);i++)
#define ppi pair<int,int>
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
const int inf = 0x3f3f3f3f;
const int N = 105;
const double pi = acos(-1.0);
const ll mod = 1e9+7;
void init(){ios::sync_with_stdio(false);cin.tie(0);} 
template<class T>inline void read(T &res)
{
	char c;T flag=1;
	while((c=getchar())<'0'||c>'9')if(c=='-')flag=-1;res=c-'0';
	while((c=getchar())>='0'&&c<='9')res=res*10+c-'0';res*=flag;
}
int main()
{
	int a,b,k,f=0;
	cin>>k>>a>>b;
	for(int i=a;i<=b;i++)
	if(i%k==0)
	{
		f=1;
		break;
	}
	if(f)cout<<"OK";
	else cout<<"NG";
	return 0;
}