using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AtCoder
{

    static class Program
    {
        static void Main()
        {
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
            //

            var N = GetInt();
            var A = GetLongArray();
            var dp = new long[N + 1][];
            for (var i = 0; i < N+1; i++)
            {
                dp[i] = new long[2];
            }
            dp[0][0] = 0;
            dp[0][1] = long.MinValue/2;
            for(int i = 1; i < N + 1; i++)
            {
                dp[i][0] = Math.Max(dp[i - 1][0] + A[i - 1], dp[i - 1][1] - A[i - 1]);
                dp[i][1] = Math.Max(dp[i - 1][0] - A[i - 1], dp[i - 1][1] + A[i - 1]);
            }
            var ans = dp[N][0];

            Console.WriteLine(ans);

            //
            Console.Out.Flush();
            Console.ReadKey();
        }

        static void Solve()
        {

        }

        static long GCD(long a, long b) { return b != 0 ? GCD(b, a % b) : a; }

        static public string GetStr() { return Console.ReadLine().Trim(); }
        static public int GetInt() { return int.Parse(Console.ReadLine()); }
        static public long GetLong() { return long.Parse(Console.ReadLine()); }
        static public string[] GetStrArray() { return Console.ReadLine().Split(' '); }
        static public int[] GetIntArray() { return Console.ReadLine().Split(' ').Select(int.Parse).ToArray(); }
        static public long[] GetLongArray() { return Console.ReadLine().Split(' ').Select(long.Parse).ToArray(); }
        static public char[] GetCharArray() { return Console.ReadLine().Split(' ').Select(char.Parse).ToArray(); }
        static public List<double> GetDoubleList() { return Console.ReadLine().Split(' ').Select(double.Parse).ToList(); }
        static public void WriteObjects<T>(IEnumerable<T> values) { foreach (var o in values) { Console.Write(o + " "); } }
        static string yesno(this bool b) { return b ? "yes" : "no"; }
        static string YesNo(this bool b) { return b ? "Yes" : "No"; }
        static string YESNO(this bool b) { return b ? "YES" : "NO"; }

        static bool eq<T, U>() => typeof(T).Equals(typeof(U));
        static T ct<T, U>(U a) => (T)Convert.ChangeType(a, typeof(T));
        static T cv<T>(string s) => eq<T, int>() ? ct<T, int>(int.Parse(s))
                           : eq<T, long>() ? ct<T, long>(long.Parse(s))
                           : eq<T, double>() ? ct<T, double>(double.Parse(s))
                           : eq<T, char>() ? ct<T, char>(s[0])
                                             : ct<T, string>(s);
        static void Multi<T>(out T a) => a = cv<T>(GetStr());
        static void Multi<T, U>(out T a, out U b)
        {
            var ar = GetStrArray(); a = cv<T>(ar[0]); b = cv<U>(ar[1]);
        }
        static void Multi<T, U, V>(out T a, out U b, out V c)
        {
            var ar = GetStrArray(); a = cv<T>(ar[0]); b = cv<U>(ar[1]); c = cv<V>(ar[2]);
        }
        static void Multi<T, U, V>(out T a, out U b, out V c, out V d)
        {
            var ar = GetStrArray(); a = cv<T>(ar[0]); b = cv<U>(ar[1]); c = cv<V>(ar[2]); d = cv<V>(ar[3]);
        }
    }
}

Measured memory_bytes: 32092