#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
using namespace std;

bool solve(const string& s)
{
    int n = s.size();
    for(int i=0; i<n; ++i){
        if(!isdigit(s[i]))
            return false;
    }

    if(n > 1 && s[0] == '0')
        return false;

    int x = stoi(s);
    return x <= 12345;
}

int main()
{
    string a, b;
    cin >> a >> b;

    if(solve(a) && solve(b))
        cout << "OK" << endl;
    else
        cout << "NG" << endl;

    return 0;
}