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

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var a = NList;
        var ans = (long)n * (n + 1) / 2;
        var tmp = 0L;
        for (var i = 0; i < n; ++i)
        {
            if (a[i] == 0)
            {
                ans -= tmp * (tmp + 1) / 2;
                tmp = 0;
            }
            else ++tmp;
        }
        WriteLine(ans - tmp * (tmp + 1) / 2);
    }
}