#include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

template<typename T = long long> inline T toInteger(const string&);

template<> inline int toInteger<int>(const string& s) {
  return stoi(s);
}

template<> inline long toInteger<long>(const string& s) {
  return stol(s);
}

template<> inline long long toInteger<long long>(const string& s) {
  return stoll(s);
}

template<typename T = long long> inline T toInteger(const string& s, int n) {
  T res = 0;
  for (char c : s) {
    if (isdigit(c)) res = res * n + c - '0';
    else if (isalpha(c)) res = res * n + tolower(c) - 'a' + 10;
  }
  return s[0] == '-' ? -res : res;
}

bool is_valid(string s) {
  for (char c : s) if (!isdigit(c)) return false;
  if (s.size() != 1u && s[0] == '0') return false;
  int n = toInteger<int>(s);
  return 0 <= n && n <= 12345;
}

int main() {
  string a, b;
  cin >> a >> b;
  cout << (is_valid(a) && is_valid(b) ? "OK" : "NG") << endl;
}