#include<iostream>
#include<algorithm>
#include<string>
#include<math.h>
#include<bitset>
#include <vector>
#include<bitset>
#include <iomanip>
#include <map>
#include <set>
#include <stack>
#include <deque>
#include <climits>
#include <queue>
using namespace std;

int main() {
	
	int  N;
	cin >> N;
	int A[250000];
	for (int i = 1; i <= N; i++)cin >> A[i];
	long long sum = N * (N + 1) / 2;
	long long count = 0;
	long long C = 0;
	for (int i = 1; i <= N; i++) {
		if (A[i] == 1) {
			C++;
		}
		else {
			count = count + C * (C + 1) / 2;
			C = 0;
		}
	}
	count = count + C * (C + 1) / 2;
	cout << sum - count;

	
}