#include <bits/stdc++.h>
#define FOR(i,bg,ed) for(ll i=(bg);i<(ed);i++)
#define REP(i,n) FOR(i,0,n)
#define MOD 1000000007
#define int long long
using namespace std;
typedef long long ll;
const int INF = 1e9;



signed main()
{
    string AB[2];

    cin >> AB[0] >> AB[1];
    REP(i,2) {
        REP(j,AB[i].length()) {
            if (AB[i].length() >= 2 && j == 0 && AB[i][j] == '0') {
                cout << "NG" << endl;
                return 0;
            }
            if ('0' <= AB[i][j] && AB[i][j] <= '9') continue;
            else {
                cout << "NG" << endl;
                return 0;
            }
        }
    }

    int A = stoi(AB[0]);
    int B = stoi(AB[1]);

    if (A > 12345 || B > 12345) {
        cout << "NG" << endl;
        return 0;
    }

    cout << "OK" << endl;
}