int part_two() {
    std::ifstream reader("data.txt");
    for (auto [i, x] : std::views::zip(std::views::iota(0),
        std::views::transform(std::views::slide(std::string{std::istreambuf_iterator<char>(reader),
            std::istreambuf_iterator<char>()}, 14), [](auto&& x) {
                return std::unordered_set(x.begin(), x.end());
            })
    )) if (x.size() == 14) return i + 14;

    return -1;
}