#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007
#define EPS 1e-10

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;

string ans;
int n;

string changes(int n){
	stringstream ss;
	string res;
	ss << n;
	ss >> res;
	return res;
}

int main(){

	while (cin >> n&&n!=-1){
		if (n == 0){
			cout << 0 << endl;
			continue;
		}
		bool f = 0;
		if (n == -1)break;
		for (int i = 9; i >= 0; i--){
			int a = 0;
			if (n >= pow(4, i)){
				a = n / pow(4, i);
			}
			if (a != 0)f = 1;
			if (f){
				ans += changes(a);
				n -= a*pow(4, i);
			}
			//cout << n << " " << a << endl;
		}
		cout << ans << endl;
		ans.clear();
	}
}