#include<iostream>
#include<string>
#include<vector>
using namespace std;

int main()
{
	while (1)
	{
		int s;
		cin >> s;
		if (s == -1)break; 
		if (s == 0)cout << 0 << endl;
		else {
			int a;
			for (a = 1; a <= s; a *= 4) {
			}
			a /= 4;
			for (int b = a; b != 0; b /= 4) {
				cout << s / b;
				s -= s / b*b;
			}
			cout << endl;
		}
	}
}