#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <tuple>
#include <map>
#include <iomanip>

#include <array>
#include <sstream>
//#include<regex>

using namespace std;

//STL output ********************************
template<typename T1, typename T2>inline std::ostream& operator << (std::ostream& os, const std::pair<T1, T2>& p) { return os << "(" << p.first << ", " << p.second << ")"; }
template<typename T>inline std::ostream &operator<<(std::ostream &os, const std::vector<T>& v) { bool first = true; os << "["; for (unsigned int i = 0; i < v.size(); i++) { if (!first)os << ", "; os << v[i]; first = false; }return os << "]"; }
inline std::ostream &operator<<(std::ostream &os, const std::vector<std::string>& v) { bool first = true; os << "["; for (unsigned int i = 0; i < v.size(); i++) { if (!first)os << ", "; os << "'" << v[i] << "'"; first = false; }return os << "]"; }
template<typename T, typename T2>void printarray(T  a[], T2 sz, T2 beg = 0) { for (T2 i = beg; i < sz; ++i) cout << a[i] << " "; cout << endl; }


int main()
{
    string a, b;
    getline(cin, a);
    getline(cin, b);
    bool flag = false;
    if (a != "0" && a[0] == '0')
        flag = true;
    if (b != "0" && b[0] == '0')
        flag = true;
    if (flag)
    {
        cout << "NG\n";
        return 0;
    }
    for (char c : a) if (!isdigit(c))
    {
        flag = true;
        break;
    }
    for (char c : b) if (!isdigit(c))
    {
        flag = true;
        break;
    }
    if (flag)
    {
        cout << "NG\n";
        return 0;
    }
    int A, B;
    istringstream ss(a + " " + b);
    ss >> A >> B;
    if (A > 12345 || B > 12345)
    {
        cout << "NG\n";
        return 0;
    }
    cout << "OK\n";
    return 0;
}