#include <bits/stdc++.h>
#include "bits/stdc++.h"
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cmath>
#include <stack>
#include <queue>
#include <cctype>
#include <stdio.h>
#include <map>
#include <unordered_map>
#include <string.h>
#include <utility>

typedef long long ll;
const int INF = 1e8;

#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
using namespace std;

typedef pair<int, int> P;

int string_int(string s){
	stringstream ss;
	ss<<s;

	int n;

	ss>>n;

	return n;
}

int main() {



	string a, b;
	cin >> a >> b;

	if (a[0] - '0' == 0 && a.length() > 1) {
		cout << "NG" << endl;
		return 0;
	}
	if (b[0] - '0' == 0 && a.length() > 1) {
		cout << "NG" << endl;
		return 0;
	}

	int tmp = 0;
	for (int i = 0; i < a.length(); i++) {
		tmp = a[i] - '0';

		if ( tmp > 9) {
			cout << "NG" << endl;
			return 0;
		}
	}
	for (int i = 0; i < b.length(); i++) {
		tmp = b[i] - '0';

		if (tmp > 9) {
			cout << "NG" << endl;
			return 0;
		}
	}

	int r,t;

	r = string_int(a);
	t = string_int(b);


	if(r>=0 && r<=12345 && t >=0 && t<=12345){
		cout<<"OK"<<endl;
	}else {
		cout << "NG" << endl;
	}

	return 0;

}