#include <iostream>
#include <algorithm>

using namespace std;

string skew;

int main()
{
	while (cin >> skew)
	{
		int res = 0;
		for (int i = 0; i < skew.size(); i ++ )
			res += (skew[i] - '0') * (pow(2, skew.size() - i) - 1);
		cout << res << endl;
	}
	return 0;
}