#include <bits/stdc++.h>
using namespace std;

bool ok(string A) {
    for (char x : A) if (!isdigit(x)) return false;
    if (A != "0" && A[0] == '0') return false;
    if (A.size() >= 6) return false;
    return stoi(A) <= 12345;
}

bool solve() {
    string A, B;
    cin >> A >> B;
    return ok(A) && ok(B);
}

int main() {
    puts(solve() ? "OK" : "NG");
}