#include <iostream>
#include <string>
using namespace std;
using ll = long long;

int main() {
    string a, b;
    cin >> a >> b;
    bool f = true;
    for(int i=0; i<a.size(); ++i) {
        f &= isdigit(a[i]);
    }
    for(int i=0; i<b.size(); ++i) {
        f &= isdigit(b[i]);
    }
    if((a[0] != '0' || a.size() == 1) && (b[0] != '0' || b.size() == 1) && f) {
        int A = stoi(a), B = stoi(b);
        if(A <= 12345 && B <= 12345) {
            cout << "OK" << endl;
        } else {
            cout << "NG" << endl;
        }
    } else {
        cout << "NG" << endl;
    }
}