#include<iterator>

template<typename T, typename Iterator>
Iterator FindImpl(const T &value,
                  Iterator first_,
                  Iterator last_,
                  std::bidirectional_iterator_tag) {
  while (first_ != last_) {
    if (*first_ == value) {
      return first_;
    }
    first_++;
  }
  return last_;
}

template<typename T, typename Iterator>
Iterator FindImpl(const T &value,
                  Iterator first_,
                  Iterator last_,
                  std::random_access_iterator_tag) {
  auto last = last_;
  last--;
  while (first_ < last) {
    Iterator mid = (last - first_) / 2 + first_;
    if (*mid < value) {
      first_ = mid + 1;
    } else {
      last = mid;
    }
  }

  if (*first_ == value) {
    return first_;
  }
  return last_;
}

template<typename T, typename Iterator>
Iterator Find(const T &value, Iterator first_, Iterator last_) {
  return FindImpl(value,
                  first_,
                  last_,
                  typename std::iterator_traits<Iterator>::iterator_category());
}