#include <bits/stdc++.h>

using namespace std;

bool solve(string s) {
    //リーディングゼロ
    if (s.length() != 1 and s[0] == '0') {
        return false;
    }

    //数字以外
    for (char i : s) {
        if (i < '0' or i > '9') {
            return false;
        }
    }

    //最大値
    return (stoi(s) <= 12345);
}

int main() {
    string s1, s2;
    cin >> s1 >> s2;

    if (solve(s1) and solve(s2)) {
        cout << "OK" << endl;
    } else {
        cout << "NG" << endl;
    }
    return 0;
}