using System.Linq;
using System.Collections.Generic;
using static System.Math;
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 b0 = new List<int>();
        var b1 = new List<int>();
        for (int i = 0; i < n; i++)
        {
            if (a[i] == 0) b0.Add(i);
            else
            {
                for (int j = 0; j < a[i] - 1; j++) b1.Add(i);
            }
        }
        var bL = b0.Count();
        var count = 0L;
        for (int i = 0; i < bL; i++) count += Abs(b0[i] - b1[i]);
        Console.WriteLine(count);
    }
}