/* -*- coding: utf-8 -*-
 *
 * 1505.cc:  No.1505 Zero-Product Ranges - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

typedef long long ll;

/* global variables */

int as[MAX_N];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", as + i);

  ll sum = (ll)n * (n + 1) / 2;
  for (int i = 0; i < n;) {
    while (i < n && as[i] == 0) i++;
    if (i >= n) break;

    int j = i;
    while (i < n && as[i] == 1) i++;
    int l = i - j;
    sum -= (ll)l * (l + 1) / 2;
  }

  printf("%lld\n", sum);
  return 0;
}