func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string second;     int ans = 0, a = 1;     cin >> second;     int k = second.length() - 1;     for (int i = 1; i < second.size(); i++) {       ans += (1 << i);     }     for (int i = 0; i < second.length(); i++) {       if (i == k) {         if (second[i] ==  4 )           ans += 1;         else           ans += 2;         continue;       }       if (second[i] ==  4 ) continue;       ans += (1 << (k - i));     }     cout << ans;     return 0;   }   