#include "bits/stdc++.h"
#define _CRT_SECURE_NO_WARNINGS
#define rep(i,n) for(int i = 0;i < n;i++)
#define REP(i,n,k) for(int i = n;i < k;i++)
#define P(p) cout << (p) << endl;
#define sP(p) cout << setprecision(15) << fixed << p << endl;
#define Pi pair<int,int>
#define IINF 1e9
#define LINF 1e18
#define vi vector<int>

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
int dx[] = { 1, -1 , 0 , 0};
int dy[] = { 0,  0,  1, -1};

unsigned long long str_to_int(std::string str) {
	unsigned long long ret;
	std::stringstream ss; ss << str;
	ss >> ret;
	return ret;
}

void solve() {
	string a, b;
	cin >> a >> b;
	bool A = false, B = false;
	rep(i, a.length()) {
		if ('1' <= a[i] and a[i] <= '9') {
			A = true;
		}
		else if (a[i] == '0') {
			if (!A and a.length() != 1) {
				P("NG");
				return;
			}
		}
		else {
			P("NG");
			return;
		}
	}
	rep(i, b.length()) {
		if ('1' <= b[i] and b[i] <= '9') {
			B = true;
		}
		else if (b[i] == '0') {
			if (!B and b.length() != 1) {
				P("NG");
				return;
			}
		}
		else {
			P("NG");
			return;
		}
	}
	int x, y;
	x = str_to_int(a);
	y = str_to_int(b);
	if (x > 12345 or y > 12345) {
		P("NG");
	}
	else {
		P("OK");
	}
}

int main() {
	solve();
	return 0;
}