#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>
#include <iterator>

typedef long long int ll;
//#include<bits/stdc++.h>


using namespace std;

int gcd(int a, int b) {
    if (a < b)swap(a, b);
    if (b == 0)return a;
    return gcd(b, a % b);
}
int lcm(int a, int b) {
    return a * b / gcd(a, b);
}


int main()
{

    int Q;
    Q = 1;
    //cin >> Q;


    while (Q--) {
        
        string a, b;
        cin >> a >> b;

        int x = 0; int y = 0;
        for (int i = 0; i < a.size(); i++) {
            if (a[i] >= '0' && a[i] <= '9') {
                x *= 10; x += a[i]-'0';
            }
            else {
                cout << "NG"; return 0;
            }
        }

        for (int i = 0; i < b.size(); i++) {
            if (b[i] >= '0' && b[i] <= '9') {
                y *= 10; y += b[i]-'0';
            }
            else {
                cout << "NG"; return 0;
            }
        }
        if (a[0]=='0' && a.size() > 1) {
            cout << "NG"; return 0;
        }
        if (b[0]=='0' && b.size() > 1) {
            cout << "NG"; return 0;
        }
        if(x>12345||y>12345) {
            
            cout << "NG"; return 0;
        }
        cout << "OK";
    }
    return 0;
}