#include <bits/stdc++.h>
#define NIL (-1)
#define ll long long
using namespace std;
const int64_t MOD = 1e9 + 7;
const int INF = INT_MAX;
const double PI = acos(-1.0);

int main() {
	int N;
	cin >> N;

	vector<int> A(N);
	for (int i = 0; i < N; i++) cin >> A[i];

	ll ones = 0;
	int cnt = 0;
	for (int i = 0; i < N; i++) {
		if (A[i]) cnt++;
		if (A[i] == 0 || i == N - 1) {
			ones += cnt*(cnt+1)/2;
			cnt = 0;
		}
	}

	ll ans = N * (N + 1) / 2 - ones;
	cout << ans << endl;
}