#include "bits/stdc++.h"
#pragma region header
#define loop(n) for ([[maybe_unused]] size_t lpcnt_ = 0; lpcnt_ < (n); ++lpcnt_)

using i32 = int;
using i64 = long long int;
using u32 = unsigned int;
using u64 = unsigned long long int;
using isize = ptrdiff_t;
using usize = size_t;

constexpr usize operator"" _uz(u64 v) { return usize(v); }

inline u64 popcount(const u64 v) {
#ifdef _MSC_VER
  return u64(__popcnt64(v));
#else
  return u64(__builtin_popcount(v));
#endif
}

class range {
  struct range_iterator {
    usize itr;
    constexpr range_iterator(const usize pos) noexcept : itr(pos) {}
    constexpr void operator++() noexcept { ++itr; }
    constexpr bool operator!=(const range_iterator& other) const noexcept {
      return itr != other.itr;
    }
    constexpr usize operator*() const noexcept { return itr; }
  };
  const range_iterator first, last;

 public:
  explicit constexpr range(const usize first_, const usize last_) noexcept
      : first(first_), last(last_) {}
  constexpr range_iterator begin() const noexcept { return first; }
  constexpr range_iterator end() const noexcept { return last; }
};

template <class F>
class rec_lambda {
  F f;

 public:
  constexpr rec_lambda(F&& f_) : f(std::forward<F>(f_)) {}
  template <class... Args>
  constexpr auto operator()(Args&&... args) const {
    return f(*this, std::forward<Args>(args)...);
  }
};

namespace cs_helper {
void zip_sort_renumber([[maybe_unused]] const std::vector<usize>& order) {}
template <class T, class... Args>
void zip_sort_renumber(const std::vector<usize>& order, std::vector<T>& head,
                       Args&... args) {
  usize n = order.size();
  assert(n == head.size());
  std::vector<T> sorted_head(n);
  for (usize i = 0; i < n; ++i) sorted_head[i] = head[order[i]];
  head = std::move(sorted_head);
  zip_sort_renumber(order, args...);
}
}  // namespace cs_helper

template <class T, class... Args>
std::vector<usize> zip_sort(std::vector<T>& head, Args&... args) {
  usize n = head.size();
  std::vector<std::pair<T, usize>> tmp(n);
  for (usize i = 0; i < n; ++i) tmp[i] = std::make_pair(head[i], i);
  std::sort(tmp.begin(), tmp.end());
  std::vector<usize> order(n);
  for (usize i = 0; i < n; ++i) order[i] = tmp[i].second;
  cs_helper::zip_sort_renumber(order, head, args...);
  return order;
}
#pragma endregion

void main_() {
  usize N;
  std::cin >> N;
  std::vector<i32> A(N);
  for (auto& el : A) std::cin >> el;
  usize lst = 0;
  u64 ans = 0;
  for (usize i : range(0, N)) {
    if (A[i] == 0) {
      ans += (i - lst + 1) * (i - lst);
      lst = i + 1;
    }
  }
  ans += (N - lst + 1) * (N - lst);
  std::cout << ((N * (N + 1) - ans) >> 1) << '\n';
  // test
}

int main() { main_(); }