#include <algorithm>
#include <cmath>
#include <iostream>
#include <numeric>
#include <queue>
#include <unordered_map>
#include <vector>
using namespace std;
using ll = long long;
#define rep(i, j, n) for (int i = j; i < (n); ++i)
#define rrep(i, j, n) for (int i = (n)-1; j <= i; --i)
#define all(a) a.begin(), a.end()
template <typename T>
std::ostream &operator<<(std::ostream &os, std::vector<T> &a) {
  for (size_t i = 0; i < a.size(); ++i) os << (i > 0 ? " " : "") << a[i];
  return os << '\n';
}
template <typename T>
std::istream &operator>>(std::istream &is, std::vector<T> &a) {
  for (T &x : a) { is >> x; }
  return is;
}
[[maybe_unused]] constexpr long long MOD = 998244353;
// constexpr int MOD = 1000000007;
[[maybe_unused]] constexpr int INF = 0x3f3f3f3f;
[[maybe_unused]] constexpr long long INFL = 0x3f3f3f3f3f3f3f3fLL;

int main() {
  cin.tie(0)->sync_with_stdio(0);
  int n;
  cin >> n;
  vector<int> a(n);
  cin >> a;
  ll ans = 0;
  // 01010101となる範囲の1の数、区間の長さから足す値が決まる
  rep(i, 0, n - 1) {
    if (i < n - 1 && a[i] == 1) {
      int j = i;
      while (j < n - 2 && a[j] != a[j + 1]) ++j;
      ll len = j - i + 1;
      ll m = (len + 2) / 2;
      ans += (len + 2) * m - m * (m + 1);
      i = j;
    }
  }
  cout << ans;
  return 0;
}