#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <sstream>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    string a, b;
    cin >> a >> b;
    auto f = [](string &s) {
        for (auto c : s) {
            if (!('0' <= c && c <= '9'))
                return false;
        }
        if (s[0] == '0' && s.size() > 1)
            return false;
        return stoi(s) <= 12345;
    };
    cout << (f(a) && f(b) ? "OK" : "NG") << endl;
    return 0;
}