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)
    {
        var ans = new List<long>();
        var now = a[0];
        var flag = now== 1? true: false;
        var tc = flag ? 1 : 0;
        for (int i = 1; i < n; i++)
        {
            if (flag)
            {
                if (now == 1)
                {
                    if (a[i] == 0) { tc++;  now = 0; }
                    else
                    {
                        ans.Add(tc);
                        tc = 1;
                        flag = true;
                        now = 1;
                    }
                }
                else
                {
                    if (a[i] == 1) { tc++; now = 1; }
                    else
                    {
                        ans.Add(tc);
                        tc = 0;
                        flag = false;
                        now = 0;
                    }
                }
            }
            else
            {
                if (a[i] == 1) { flag = true; tc++;  now = 1; }
                else now = 0;
            }
        }
        if (flag && now == 1) ans.Add(tc - 1);
        if (flag && now == 0) ans.Add(tc );
        var res = 0L;
        foreach(var x in ans)
        {
            if (x % 2 == 0) res += (x / 2) * (x / 2 + 1);
            else res += (x + 1) * (x + 1) / 4L;
        }
        Console.WriteLine(res);
    }
}