#include <iostream>
using namespace std;
bool ok(string S){
	int N = S.size();
	if (N > 1 && S[0] == '0'){
		return false;
	}
	for (int i = 0; i < N; i++){
		if (!('0' <= S[i] && S[i] <= '9')){
			return false;
		}
	}
	if (stoi(S) > 12345){
		return false;
	}
	return true;
}
int main(){
	string A;
	cin >> A;
	string B;
	cin >> B;
	if (ok(A) && ok(B)){
		cout << "OK" << endl;
	} else {
		cout << "NG" << endl;
	}
}