#include <map>
#include <vector>
#include <fstream>
#include <sstream>
#include <iostream>
#include <set>
#include <iomanip>

using namespace std;

int main()
{
    std::map<std::string, std::set<std::string>> people { };
    std::map<std::string, unsigned> movies { };
    std::cout << "On each line, enter a person's name followed"
              << " by their movie preferences." << std::endl
              << "To exit, press ctrl+D." << std::endl;

    std::string name;
    while (std::cin >> name)
    {
        std::string line;
        getline(std::cin, line);

        std::istringstream iss { line };
        std::string movie;
        while (iss >> movie)
        {
            auto [it, success] = people[name].insert(movie);
            if (success)
            {
                ++movies[movie];
            }
        }
    }
    std::cout << std::endl;

    std::cout << "The candidates for watching: " << std::endl;
    for (auto&& [movie, count] : movies)
    {
        if (count == people.size())
        {
            std::cout << " - " << movie << std::endl;
        }
    }
}