#include <iostream>
#include <string>
#include <cmath>
using namespace std;

int main() {
    string str;
    while (getline(cin, str)) {
        int num = 0;
        for(int i = 0; i < str.length(); i ++){
            num += (str[i]-'0') * (pow(2, str.length()-i) -1);
        }
        cout << num << endl;
    }
    return 0;
}