#include <iostream>
#include <string>
using namespace std;
int main(void) {
	string a, b;
	cin >> a >> b;
	bool ok_a = true, ok_b = true;
	if (a[0] == '0' && a.size() != 1) ok_a = false;
	if (b[0] == '0' && b.size() != 1) ok_b = false;
	for (int i = 0; i < a.size(); ++i) {
		if (a[i] < 48 || 57 < a[i]) ok_a = false;
	}
	for (int i = 0; i < b.size(); ++i) {
		if (b[i] < 48 || 57 < b[i]) ok_b = false;
	}
	if (ok_a && ok_b) {
		int A = stoi(a), B = stoi(b);
		if (A > 12345) ok_a = false;
		if (B > 12345) ok_b = false;
	}
	cout << (ok_a && ok_b ? "OK" : "NG") << endl;
	return 0;
}