#include<iostream>
#include<string>
#include<algorithm>
#include<map>
#include<vector>
#include<cmath>
#include<cstdio>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb(in,tmp) in.push_back(tmp)
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
using namespace std;
int main(){
  int n;
  while(cin>>n,n+1){
    if(!n){cout<<0<<endl;continue;}
    vector<int>out;
    while(n){
      pb(out,n%4);
      n/=4;
    }
    rep(i,out.size())cout<<out[out.size()-i-1];
    cout<<endl;
  }


}