#include<iterator>

template<typename T, typename Iterator>
Iterator FindImpl(const T &value,
                  Iterator first,
                  Iterator last,
                  std::random_access_iterator_tag) {
  auto if_no = 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 if_no;
}

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