#include <iostream>
#include <string>

int main() {
    using namespace std;
    auto is_integer_le_12345 = [&](string s) -> bool {
        if (s.size() > 5 || s.size() < 1) { return false; }
        if (s.size() > 1 && s[0] == '0') { return false; }
        for (char c : s) {
            if (c < '0' || c > '9') { return false; }
        }
        int n = stoi(s);
        return n >= 0 && n <= 12345;
    };
    string s, t;
    cin >> s >> t;
    bool ans = is_integer_le_12345(s) && is_integer_le_12345(t);
    cout << (ans ? "OK\n" : "NG\n");
}