#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>

using namespace std;

int main()
{
    string s, t;
    cin >> s;
    for(int i=s.size()-1;i>=0;)
    {
        int j = max(0, i-4);
        int sum = 0;
        for(int k=i;k>=j;k--)
        {
            if(s[k] == '1') sum += pow(2, i-k); 
        }
        if(sum >= 10) t += (sum-10+'A');
        else t += (sum + '0');
        i=j-1;
    }
    
    reverse(t.begin(), t.end());
    cout << t << endl;
    return 0;
}