#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define ll long long
#define INF (1 << 30)
#define INFLL (1LL << 60)

#define FOR(i,a,b) for(ll i = (a);i<(b);i++)
#define REP(i,a) FOR(i,0,(a))
#define MP make_pair

bool check(string str){
	int num = 0;
	for(int i = 0;i < str.size();i++){
		if('0' <=  str[i] && str[i] <= '9'){
			num *= 10;
			num += str[i] - '0';
		}else{
			return true;
		}
	}

	if(num > 12345) return true;

	return false;
}

int main() {
	string a,b;
	cin >> a >> b;
	bool flag = false;

	if((a.size() != 1 && a[0] == '0') || (b.size() != 1 && b[0] == '0')) flag = true;
	if(flag == false){
		if(check(a) || check(b)){
			flag = true;
		}
	}

	if(flag) cout << "NG" << endl;
	else cout << "OK" << endl;
	return 0;
}