using System;
using System.Collections.Generic;
using static System.Console;
using System.Linq;

class yuki325
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(int n) => Enumerable.Repeat(0, n).Select(_ => NList).ToArray();
    static void Main()
    {
        var n = NN;
        var a = NList;
        var cur = 0;
        var res = 0L;
        for (var i = n - 2; i >= 0; --i)
        {
            if (i < n - 2 && a[i] != a[i + 1]) ++cur;
            else cur = 0;
            if (a[i] == 1)
            {
                res += cur + 1;
            }
        }
        WriteLine(res);
    }
}