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


string s;
int main() {
	cin >> s;
	long long sum = 0;
	int count = 0;
	for (int i = s.length() - 1; i >= 0; i--,count++) {
		int temp = s[i] - '0';
		sum += temp * (pow(2, count + 1) - 1);
	}
	printf("%lld", sum);
}