using System;
using System.IO;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using E = System.Linq.Enumerable;

partial class Solver
{
    public void Run()
    {
        var N = ni();
        var Y = ni(N);

        long ans = 0;

        Array.Sort(Y);

        var dp = new long[N];

        for (int i = 0; i < N; i++)
        {
            var v = long.MaxValue >> 10;
            if (i - 1 >= 0)
            {
                v = Math.Min(v, (i - 2 >= 0 ? dp[i - 2] : 0) + (Y[i] - Y[i - 1]));
            }
            if (i - 2 >= 0)
            {
                v = Math.Min(v, (i - 3 >= 0 ? dp[i - 3] : 0) + (Y[i] - Y[i - 2]));
            }
            dp[i] = v;
        }

        cout.WriteLine(dp[N - 1]);
    }
}

public class SumTable
{
    private readonly long[] sumArray;
    public SumTable(long[] array)
    {
        sumArray = new long[array.Length + 1];
        Array.Copy(array, 0, sumArray, 1, array.Length);
        for (int i = 1; i < sumArray.Length; i++)
        {
            sumArray[i] += sumArray[i - 1];
        }
    }

    public long Sum(int begin, int end)
    {
        if (begin >= end) return 0;
        return sumArray[end] - sumArray[begin];
    }
}

public class ModMatrix
{
    public int Row { get; private set; }
    public int Col { get; private set; }
    public int Mod { get; private set; }
    private long[] Data;
    public ModMatrix(int row, int col, int mod)
    {
        this.Row = row;
        this.Col = col;
        this.Data = new long[Row * Col];
        this.Mod = mod;
    }

    public ModMatrix(long[,] array, int mod)
        : this(array.GetLength(0), array.GetLength(1), mod)
    {
        int index = 0;
        for (int i = 0; i < Row; i++)
        {
            for (int j = 0; j < Col; j++)
            {
                Data[index++] = array[i, j] % mod;
            }
        }
    }

    public long this[int row, int col]
    {
        set
        {
            Data[row * Col + col] = value;
        }
        get
        {
            return Data[row * Col + col];
        }
    }

    static public ModMatrix UnitMatrix(int n, int mod)
    {
        var matrix = new ModMatrix(n, n, mod);
        for (int i = 0; i < n; i++)
        {
            matrix[i, i] = 1;
        }
        return matrix;
    }

    static public ModMatrix operator +(ModMatrix A, ModMatrix B)
    {
        if (A.Mod != B.Mod) throw new InvalidOperationException("A.Mod must be equal to B.Mod");
        var C = new ModMatrix(A.Row, A.Col, A.Mod);
        for (int i = 0; i < C.Data.Length; i++)
        {
            C.Data[i] = (A.Data[i] + B.Data[i] + A.Mod) % A.Mod;
        }
        return C;
    }

    static public ModMatrix operator -(ModMatrix A, ModMatrix B)
    {
        if (A.Mod != B.Mod) throw new InvalidOperationException("A.Mod must be equal to B.Mod");
        var C = new ModMatrix(A.Row, A.Col, A.Mod);
        for (int i = 0; i < C.Data.Length; i++)
        {
            C.Data[i] = (A.Data[i] - B.Data[i] + A.Mod) % A.Mod;
        }
        return C;
    }

    static public ModMatrix operator *(ModMatrix A, ModMatrix B)
    {
        if (A.Mod != B.Mod) throw new InvalidOperationException("A.Mod must be equal to B.Mod");
        var C = new ModMatrix(A.Row, B.Col, A.Mod);
        for (int i = 0; i < A.Row; i++)
        {
            for (int j = 0; j < B.Col; j++)
            {
                var val = C[i, j];
                for (int k = 0; k < A.Col; k++) val = (val + A[i, k] * B[k, j]) % A.Mod;
                if (val < 0) val += A.Mod;
                C[i, j] = val;
            }
        }
        return C;
    }

    static public ModMatrix Pow(ModMatrix A, long n)
    {
        if (n == 0) return UnitMatrix(A.Row, A.Mod);
        if (n == 1) return A;
        ModMatrix result = A.Clone(), t = A.Clone(); n--;
        for (; n > 0; n >>= 1)
        {
            if ((n & 1) != 0) result = result * t;
            t = t * t;
        }

        return result;
    }

    public ModMatrix Clone()
    {
        return new ModMatrix(Row, Col, Mod) { Data = Data.Clone() as long[] };
    }
}
// PREWRITEN CODE BEGINS FROM HERE
partial class Solver : Scanner
{
    public static void Main(string[] args)
    {
#if LOCAL
        new Solver(Console.In, Console.Out).Run();
#else
        Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        new Solver(Console.In, Console.Out).Run();
        Console.Out.Flush();
#endif
    }

#pragma warning disable IDE0052
    private readonly TextReader cin;
    private readonly TextWriter cout;
#pragma warning restore IDE0052

    public Solver(TextReader reader, TextWriter writer)
        : base(reader)
    {
        this.cin = reader;
        this.cout = writer;
    }
    public Solver(string input, TextWriter writer)
        : this(new StringReader(input), writer)
    {
    }

#pragma warning disable IDE1006
#pragma warning disable IDE0051
    private int ni() { return NextInt(); }
    private int[] ni(int n) { return NextIntArray(n); }
    private long nl() { return NextLong(); }
    private long[] nl(int n) { return NextLongArray(n); }
    private double nd() { return NextDouble(); }
    private double[] nd(int n) { return NextDoubleArray(n); }
    private string ns() { return Next(); }
    private string[] ns(int n) { return NextArray(n); }
#pragma warning restore IDE1006
#pragma warning restore IDE0051
}

public static class LinqPadExtension
{
    static public T Dump<T>(this T obj)
    {
#if LOCAL
        return LINQPad.Extensions.Dump(obj);
#else
        return obj;
#endif
    }
}
public class Scanner
{
    private readonly TextReader Reader;
    private readonly Queue<string> TokenQueue = new Queue<string>();
    private readonly CultureInfo ci = CultureInfo.InvariantCulture;

    public Scanner()
        : this(Console.In)
    {
    }

    public Scanner(TextReader reader)
    {
        this.Reader = reader;
    }

    public int NextInt() { return int.Parse(Next(), ci); }
    public long NextLong() { return long.Parse(Next(), ci); }
    public double NextDouble() { return double.Parse(Next(), ci); }
    public string[] NextArray(int size)
    {
        var array = new string[size];
        for (int i = 0; i < size; i++) array[i] = Next();
        return array;
    }
    public int[] NextIntArray(int size)
    {
        var array = new int[size];
        for (int i = 0; i < size; i++) array[i] = NextInt();
        return array;
    }

    public long[] NextLongArray(int size)
    {
        var array = new long[size];
        for (int i = 0; i < size; i++) array[i] = NextLong();
        return array;
    }

    public double[] NextDoubleArray(int size)
    {
        var array = new double[size];
        for (int i = 0; i < size; i++) array[i] = NextDouble();
        return array;
    }

    public string Next()
    {
        if (TokenQueue.Count == 0)
        {
            if (!StockTokens()) throw new InvalidOperationException();
        }
        return TokenQueue.Dequeue();
    }

    public bool HasNext()
    {
        if (TokenQueue.Count > 0)
            return true;
        return StockTokens();
    }
    static readonly char[] _separator = new[] { ' ' };
    private bool StockTokens()
    {
        while (true)
        {
            var line = Reader.ReadLine();
            if (line == null) return false;
            var tokens = line.Split(_separator, StringSplitOptions.RemoveEmptyEntries);
            if (tokens.Length == 0) continue;
            foreach (var token in tokens)
                TokenQueue.Enqueue(token);
            return true;
        }
    }
}