#include <bits/stdc++.h>

using namespace std;

int main(void) {
  string a, b;
  cin >> a >> b;

  bool ok = true;
  for (int i = 0; i < a.size(); i++) {
    ok &= isdigit(a[i]);
  }
  for (int i = 0; i < b.size(); i++) {
    ok &= isdigit(b[i]);
  }

  if (ok) {
    if (a.size() == 5) ok &= a <= "12345";
    if (b.size() == 5) ok &= b <= "12345";
    if (a != "0") ok &= a[0] != '0';
    if (b != "0") ok &= b[0] != '0';
  }

  cout << (ok ? "OK" : "NG") << endl;

  return 0;
}