func_code_string: #include <bits/stdc++.h>   using namespace std;   double pi = acos(-1);   void OJ() {}   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     ;     vector<string> v;     long long num = 0, k = 0;     v.push_back( 4 ), v.push_back( 7 );     while (1) {       long long n = v.size();       for (long long i = 0; i < n; i++) {         for (long long j = k; j < n; j++) {           string s = v[i] + v[j];           v.push_back(s);           num = max(num, stoll(s, nullptr, 10));           if (num >= 1e9) break;         }         if (num >= 1e9) break;       }       k = n;       if (num >= 1e9) break;     }     vector<long long> ar;     for (auto s : v) {       ar.push_back(stoll(s, nullptr, 10));     }     long long i = 0;     sort(ar.begin(), ar.end());     unordered_map<long long, long long> m;     for (auto s : ar) {       if (m.find(s) == m.end()) m[s] = (++i);     }     long long in;     cin >> in;     cout << m[in];   }   