#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using PII = std::pair<int, int>;
using PLL = std::pair<ll, ll>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)

bool sisdigit(string s)
{
    bool ret = true;
    rep(i, s.length())
    {
        if (!isdigit(s[i]))
            ret = false;
    }
    return ret;
}

bool sislimit(string s, int n)
{
    if (s == "0")
        return true;
    int a = stoi(s);
    return (s[0] != '0' && a <= n);
}

int main()
{

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    const int lim = 12345;
    string a, b;
    char ca, cb;
    cin >> a >> b;
    bool aisok, bisok;

    aisok = sisdigit(a);
    bisok = sisdigit(b);

    if (aisok)
        aisok = sislimit(a, lim);
    if (bisok)
        bisok = sislimit(b, lim);


    cout << ((aisok && bisok) ? "OK" : "NG") << endl;

    return 0;
}