#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>
#include <cctype>

using namespace std;

bool check(string s) {
	for (char c : s) {
		if (!isdigit(c)) {
			return false;
		}
	}

	if (s.size() > 1 && s[0] == '0') {
		return false;
	}

	return stoi(s) <= 12345;
}

int main() {
	string a, b;

	cin >> a >> b;

	bool ret = check(a) && check(b);
	cout << (ret ? "OK" : "NG") << endl;

	return 0;
}