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

string add(string a, char digit) {
 string b = "";
 b += digit;
 if (a.length() > b.length()) b.insert(0, a.length() - b.length(), '0');
   else a.insert(0, b.length() - a.length(), '0');

 int sum, carry = 0;
 string c = "";
 for (int i = a.length() - 1; i >= 0; i--) {
  sum = int(a[i]) - 48 + int(b[i]) - 48 + carry;

  carry= sum / 10;

  c = char(sum % 10 + 48) + c;
  }
  if (carry > 0) c = '1' + c;
  return c;
}

string multiply(string a, int n2) {
 string c = "";
 int carry = 0, s;
 for (int i = a.length() - 1; i >= 0; i--) {
  s = (int(a[i]) - 48) * n2 + carry;

  carry = s / 10;

  c = char(s % 10 + 48) + c;
 }
 while (carry > 0) {
  c = char(carry % 10 + 48) + c;

  carry /= 10;
 }
 return c;
}
int main() {
 freopen("BAI3.INP", "r", stdin);
 freopen("BAI3.OUT", "w", stdout);
 string s, c = "0";
 cin >> s;
 for (int i = 0; i < s.length(); i++) c = add(multiply(c, 2), s[i]);
 cout << c;
}