#include <bits/stdc++.h>
using namespace std;

int main()
{
    string s;
    while (cin >> s)
    {
        int sum = 0;
        int w = 1;
        for (int i = s.size() - 1; i >= 0; -- i, w = 2 * w + 1)
        {
            if (s[i] == '0') continue;
            sum += (s[i] - '0') * w;
        }
        cout << sum << endl;
    }
    return 0;
}