#include <algorithm>
#include <iostream>
#include <string>

using namespace std;

bool ok(const string& s) {
    return all_of(s.begin(), s.end(),
                  [](char ch) { return '0' <= ch && ch <= '9'; }) &&
           (s[0] != '0' || s.length() == 1) && (stoi(s) <= 12345);
}

int main() {
    string a, b;
    cin >> a >> b;

    if (ok(a) && ok(b)) {
        cout << "OK" << endl;
    } else {
        cout << "NG" << endl;
    }
}