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<string>
#include<cstring>
#include <cstdio>
#include<utility>
#include<algorithm>
#include<vector>
#include<cmath>
#include<map>
#include<bitset>
#include<queue>
#include<stack>
#include<set>
#include <limits>
#include <climits>
#include <numeric>
#include<cassert>
using namespace std;
typedef long long ll;
typedef vector<ll>VI;
typedef pair<ll,ll>P;
typedef pair<double,double>P_D;
#define PI 3.1415926535897932384626433832795
#define rep(i, n) for (ll i = 0; i < (ll)n; i++)
#define reprev(i, n) for (ll i = (ll)n - 1; i >= 0; i--)
#define bitrep(bit,A) for(int bit=A; ;bit=(bit-1)&A)
#define ALL(a)  (a).begin(),(a).end()
#define c_max(a, b) (((ll)a)>((ll)b)?(a):(b))
#define c_min(a,b) (((ll)a)<((ll)b)?(a):(b))
#define chmax(x,a) x=c_max(x,a)
#define chmin(x,a) x=c_min(x,a)
#define vmax(v) *max_element(ALL(v))
#define vmin(v) *min_element(ALL(v))
#define fi first
#define se second
#define MAX 100100//5
#define MAX_N 200100
#define MAX_B 1001001//6
#define MAX_S 10010010//7
#define SENTINEL 2000000000//9
#define NIL -1
#define MOD 1000000007
#define INF 1<<30
#define INFTY 1000000000000000001LL
#define MAX_INT INT_MAX
#define Endl '\n'
#define mian() main()
#define greater greater<int>()
ll GCD(ll a,ll b){return b?GCD(b,a%b):a;}
ll mod_pow(ll x,ll n,ll mod=(ll)MOD){ll res=1;while(n>0){
if(n&1)res=res*x%mod;x=x*x%mod;n>>=1;}return res;}
using Graph=vector<vector<P> >;
int main(){
    int k,a,b;cin>>k>>a>>b;
    for(int i=a;i<=b;i++){
        if(i%k==0){cout<<"OK"<<endl;return 0;}
    }
    cout<<"NG"<<endl;
}