#include <iostream>
#include <string>
using namespace std;
int main()
{
    string a, b;
    cin >> a >> b;
    bool f = true;
    
    for (int i = 0; i < a.size(); i++) {
        f &= isdigit(a[i]);
    }
    for (int i = 0; i < b.size(); i++) {
        f &= isdigit(b[i]);
    }
    
    if ( (a[0] != '0' || a.size() == 1) && (b[0] != '0' || b.size() == 1) && f)
    {
        int A = stoi(a), B = stoi(b);
        if (A <= 12345 && B <= 12345)
        {
            cout << "OK" << endl;
        }
        else
        {
            cout << "NG" << endl;
        }
    }
    else
    {
        cout << "NG" << endl;
    }
    
    return 0;
}