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();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var y = NList;
        Array.Sort(y);
        var ans = 0L;
        for (var i = 0; i < n; ++i) ans += Math.Abs(y[i] - y[n / 2]);
        WriteLine(ans); 
    }
}