text: #include <iostream>
  #include <sstream>
  #include <boost/algorithm/string/split.hpp>
  #include <boost/algorithm/string/classification.hpp>
  #include <iterator>
  #include <vector>
  #include <unordered_set>
  
  int main() {
      std::string line;
      size_t correct = 0;
  
      while(std::getline(std::cin, line)) {
          if (line.empty()) {
              break;
          }
  
          std::vector<std::string> words;
          boost::algorithm::split(words, line, boost::is_any_of(" "), boost::algorithm::token_compress_on);
  
          std::unordered_set<std::string> set;
          std::copy(std::cbegin(words), std::cend(words),
                    std::insert_iterator<std::unordered_set<std::string>>(set, set.begin()));
  
          if (words.size() == set.size()) {
              ++correct;
          }
      }
      std::cout << "correct: " << correct << "\n";
  }
  