#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

inline bool isDigit(string s) {
  if (s[0] == '0' && s.size() > 1) return false;
  return all_of(s.begin(), s.end(), ::isdigit);
}

int main() {
  string a, b;
  cin >> a >> b;
  if (isDigit(a) && isDigit(b)) {
    int x = stoi(a), y = stoi(b);
    if (0 <= x && x <= 12345 && 0 <= y && y <= 12345) {
      cout << "OK" << endl;
      return 0;
    }
  }
  cout << "NG" << endl;
  return 0;
}