#include <iostream>
 
using namespace std;
 
int main()
{
    int n;
 
    while (true)
    {
        cin >> n;
 
        if (n == -1) { break; }
 
        if (n == 0)
        {
            cout << "0" << endl;
        }
        else
        {
            int t = (1 << 20);
 
            for (int i = 0; i < 10; i++)
            {
                t /= 4;
 
                if (n / t)
                {
                    cout << (n / t) % 4;
                }
            }
 
            cout << endl;
        }
    }
 
    return 0;
}