func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     srand(time(NULL));     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.setf(ios::fixed);     cout.precision(0);     long long n;     cin >> n;     string s;     char y =  a ;     while (n != 0) {       s.push_back(y);       int t = 1;       while (t <= n) {         s.push_back(y);         n -= t;         t++;       }       y++;     }     if (s.size() == 0) s.push_back( a );     cout << s;   }   