text: #include <cstdlib>
  #include    <iostream>
      using   std::cin;
      using   std::cout;
      using   std::endl;
  #include <fstream>
      using   std::ofstream;
  #include <sstream>
      using   std::stringstream;
  #include    <string>
      using   std::string;
      using   std::to_string;
  #include <filesystem>
      using   std::filesystem::path;
      using   std::filesystem::exists;
  #include <stdexcept>
      using   std::exception;
  #include <deque>
      using   std::deque;
  