#include"bits/stdc++.h"
using namespace std;
int main() {
	string a, b; cin >> a >> b; int al = a.length(); int bl = b.length();
	if ((a[0] == '0'&&al != 1) || (b[0] == '0'&&bl != 1)) { cout << "NG" << endl; return 0; }
	int n = 0; int m = 0;
	for (int i = 0; i < al; i++) {
		if ('0' <= a[i] && a[i] <= '9')n += (a[i] - '0')*pow(10, al - i - 1);
		else { cout << "NG" << endl; return 0; }
	}
	for (int i = 0; i < bl; i++) {
		if ('0' <= b[i] && b[i] <= '9')m += (b[i] - '0')*pow(10, bl - i - 1);
		else { cout << "NG" << endl; return 0; }
	}
	cout << ((n <= 12345 && m <= 12345) ? "OK" : "NG") << endl;
}