using System.Collections.Generic;
using System;

public class Hello
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        getAns(n, a);
    }
    static void getAns ( int n, int[] a)
    {
        if (n == 1) { Console.WriteLine(a[0] == 0? 1:0); return; }
        var pre = a[0] == 0 ? 0 : -1;
        var d = new Dictionary<long, long>();
        for (int i = 1; i < n; i++)
        {
            if (a[i] == 0)
            {
                var t = pre == -1 ? i : i - pre - 1;
                if (d.ContainsKey(t)) d[t]++;
                else d[t] = 1;
                pre = i;
            }
        }
        var e = n - pre - 1;
        if (e > 0)
        {
            if (d.ContainsKey(e)) d[e]++;
            else d[e] = 1;
        }
        var sum = 0L;
        foreach (var x in d)
            sum += (x.Key + (x.Key) * (x.Key - 1) / 2L) * x.Value;
        var ans = n + n * (n - 1L) / 2L - sum;
        Console.WriteLine(ans);
    }
}