using System;
using System.Text;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using static System.Console;
using static System.Math;
using System.Threading;
using System.Threading.Tasks;

namespace AtCoder
{
    public class Program
    {
        public static void Main(string[] args)
        {
            new Program().Solve(new ConsoleInput(Console.In, ' '));
        }

        public void Solve(ConsoleInput cin)
        {
            var N = cin.ReadInt;
            var A = cin.ReadLongArray(N);

            var Ap = new List<long>();
            var An = new List<long>();
            foreach (var a in A)
            {
                if (a > 0)
                {
                    Ap.Add(a);
                }
                else
                {
                    An.Add(a);
                }
            }

            var ans = 0L;
            
            if (Ap.Count == 0)
            {
                if (An.Count % 2 == 0)
                {
                    ans = -An.Sum();
                }
                else
                {
                    ans = -An.Sum() + An.Max() * 2;
                }
            }
            else if (An.Count == 0)
            {
                ans = Ap.Sum();
            }
            else if (An.Count % 2 == 0)
            {
                ans = Ap.Sum() - An.Sum();
            }
            else
            {
                if (Ap.Count > 0 && Ap.Min() + An.Max() < 0)
                {
                    ans = Ap.Sum() - An.Sum() - Ap.Min() * 2;
                }
                else
                {
                    ans = Ap.Sum() - An.Sum() + An.Max() * 2;
                }
            }
            Console.WriteLine(ans);
        }

        static int gcd(int a, int b)
        {
            return b == 0 ? a : gcd(b, a % b);
        }
    }

    public class ConsoleInput
    {
        private readonly System.IO.TextReader _stream;
        private char _separator = ' ';
        private Queue<string> inputStream;
        public ConsoleInput(System.IO.TextReader stream, char separator = ' ')
        {
            this._separator = separator;
            this._stream = stream;
            inputStream = new Queue<string>();
        }
        public string Read
        {
            get
            {
                if (inputStream.Count != 0) return inputStream.Dequeue();
                string[] tmp = _stream.ReadLine().Split(_separator);
                for (int i = 0; i < tmp.Length; ++i)
                    inputStream.Enqueue(tmp[i]);
                return inputStream.Dequeue();
            }
        }
        public string ReadLine { get { return _stream.ReadLine(); }}
        public int ReadInt { get { return int.Parse(Read); }}
        public long ReadLong { get { return long.Parse(Read); }}
        public double ReadDouble { get { return double.Parse(Read); }}
        public string[] ReadStrArray(long N) { var ret = new string[N]; for (long i = 0; i < N; ++i) ret[i] = Read; return ret;}
        public int[] ReadIntArray(long N) { var ret = new int[N]; for (long i = 0; i < N; ++i) ret[i] = ReadInt; return ret;}
        public long[] ReadLongArray(long N) { var ret = new long[N]; for (long i = 0; i < N; ++i) ret[i] = ReadLong; return ret;}
    }
}


Measured memory_bytes: 31068