#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <map>
#include <iomanip>
#include <math.h> 
#include <stack>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <tuple>
#include <cctype>
#include <ctype.h>
#include <set>
#include <sstream>

using namespace std;

int main(){
	int i, j, k;
	string a, b;
	bool flag = false;


	cin >> a >> b;



	for (i = 0; i < a.length(); i++) {
		if (a[i] - 48 >= 0 && a[i] - 48 <= 9) {

		}
		else {
			flag = true;
		}
	}

	for (i = 0; i < b.length(); i++) {
		if (b[i] - 48 >= 0 && b[i] - 48 <= 9) {

		}
		else {
			flag = true;
		}
	}

	if ((a.length()>=2 && a[0] == '0') || (b.length()>=2 && b[0] == '0')) {
		flag = true;
	}

	if (flag == false) {
		if (stoi(a) > 12345) {
			flag = true;
		}

		if (stoi(b) > 12345) {
			flag = true;
		}

	}


	if (flag == false) {
		cout << "OK" << endl;
	}
	else {
		cout << "NG" << endl;
	}






	getchar();
	getchar();
	return 0;
}