using System;
using System.Linq;
using System.Collections.Generic;

namespace Contest
{
    class Program
    {
        static void Main(string[] args)
        {
            ABC125.D();
        }

        class ABC125
        {
            public static void A()
            {
                var A = Read.Int();
                var B = Read.Int();
                var T = Read.Int();
                Console.WriteLine(T / A * B);
            }
            public static void B()
            {
                var N = Read.Int();
                var V = Read.IntN();
                var C = Read.IntN();
                var max = Enumerable.Range(0, N).Select(i => Math.Max(0, V[i] - C[i])).Sum();
                Console.WriteLine(max);
            }
            public static void C()
            {
                var N = Read.Int();
                var A = Read.IntN();
                long[] leftGCD = new long[N + 2];
                long[] rightGCD = new long[N + 2];
                for(int i = 0; i < N; ++i)
                {
                    leftGCD[i + 1] = Util.GCD(leftGCD[i], A[i]);
                    rightGCD[i + 1] = Util.GCD(rightGCD[i], A[N - i - 1]);
                }
                long max = 0;
                for(int i = 0; i < N; ++i)
                {
                    max = Math.Max(max, Util.GCD(leftGCD[i], rightGCD[N - i - 1]));
                }
                Console.WriteLine(max);
            }
            public static void D()
            {
                var N = Read.Int();
                var A = Read.LongN();
                long ideal = A.Select(x => Math.Abs(x)).Sum();
                if (A.Count(x => x < 0) % 2 == 1)
                {
                    ideal -= A.Select(x => Math.Abs(x)).Min() * 2;
                }
                Console.WriteLine(ideal);
            }
        }

        class Util
        {
            public static long GCD(long a, long b)
            {
                while (b > 0)
                {
                    var c = a % b;
                    a = b;
                    b = c;
                }
                return a;
            }
        }

        static class Read
        {
            static Queue<string> queue = new Queue<string>();
            static void Enqueue() { var ss = Console.ReadLine().Split(' '); foreach (var s in ss) { queue.Enqueue(s); } }
            public static int Int() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt32(queue.Dequeue()); }
            public static long Long() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt64(queue.Dequeue()); }
            public static string Str() { if (queue.Count == 0) { Enqueue(); } return queue.Dequeue(); }
            public static int[] IntN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt32(s)).ToArray(); }
            public static long[] LongN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt64(s)).ToArray(); }
            public static string[] StrN() { return Console.ReadLine().Split(' '); }
            public static Tuple<int, int>[] TupleInt(int n) { List<Tuple<int, int>> list = new List<Tuple<int, int>>(); for (int i = 0; i < n; ++i) { var ab = Read.IntN(); list.Add(new Tuple<int, int>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<long, long>[] TupleLong(int n) { List<Tuple<long, long>> list = new List<Tuple<long, long>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<long, long>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<string, string>[] TupleStr(int n) { List<Tuple<string, string>> list = new List<Tuple<string, string>>(); for (int i = 0; i < n; ++i) { var ab = Read.StrN(); list.Add(new Tuple<string, string>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<double, double>[] TupleDouble(int n) { List<Tuple<double, double>> list = new List<Tuple<double, double>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<double, double>(ab[0], ab[1])); } return list.ToArray(); }
            public static long[,] LongMatrix(int r, int c)
            {
                var mat = new long[r, c];
                for (int i = 0; i < r; ++i)
                {
                    var x = Read.LongN();
                    for (int j = 0; j < c; ++j)
                    {
                        mat[i, j] = x[j];
                    }
                }
                return mat;
            }
            public static Dictionary<int, HashSet<int>> AdjacencyList(int N, int M)
            {
                Dictionary<int, HashSet<int>> dict = new Dictionary<int, HashSet<int>>();
                for (int i = 0; i <= N; ++i)
                {
                    dict.Add(i, new HashSet<int>());
                }
                for (int i = 0; i < M; ++i)
                {
                    var ab = Read.IntN();
                    dict[ab[0]].Add(ab[1]);
                    dict[ab[1]].Add(ab[0]);
                }
                return dict;
            }
        }
    }
}


Measured memory_bytes: 29404