#include "bits/stdc++.h"
#include<unordered_map>
#include<unordered_set>
#pragma warning(disable:4996)
using namespace std;
using ld = long double;
template<class T>
using Table = vector<vector<T>>;
const ld eps=1e-9;

//// < "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\a.txt" > "D:\D_Download\Visual Studio 2015\Projects\programing_contest_c++\Debug\b.answer"
int main() {
	while (1) {
		int n; cin >> n;
		if (n == -1)break;
		else if (n == 0) {
			cout << 0 << endl;
		}
		else {
			string st;
			while (n) {
				st.push_back(n%4 + '0');
				n /= 4;
			}
			reverse(st.begin(), st.end());
			cout << st << endl;
		}
	}
	return 0;
}