using System;
using System.Collections.Generic;
using System.Linq;
using System.Globalization;
using System.IO;
using System.Text;

#region code challenges entry point
#if !SOLVER_ATWORKSPACE
class Program{static void Main(string[] args){using (var output = new CC.FormattedStreamWriter(Console.OpenStandardOutput())) using (var error = new CC.FormattedStreamWriter(Console.OpenStandardError())) using (var input = new CC.BufferedStreamReader(Console.OpenStandardInput()))new CC.Solver(input, output, error).Do();}}
#endif
#endregion

#region code helpers boilerplate
namespace CC
{
    class BufferedStreamReader : StreamReader { const int QUEUE_INITSIZE = 10000; public BufferedStreamReader(String fileName) : base(fileName) { } public BufferedStreamReader(Stream stream) : base(stream) { } private Queue<string> buffer = new Queue<string>(QUEUE_INITSIZE); public override string ReadLine() { if (buffer.Count > 0) throw new InvalidOperationException("must read from buffer first"); return base.ReadLine(); } public string ReadToken() { while (buffer.Count == 0) { base.ReadLine().Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries).ToList().ForEach((t) => { buffer.Enqueue(t); }); } return buffer.Dequeue(); } public void ResetBuffer() { buffer = new Queue<string>(QUEUE_INITSIZE); } }
    class FormattedStreamWriter : StreamWriter { public FormattedStreamWriter(Stream stream) : base(stream) { } public FormattedStreamWriter(string filePath) : base(filePath) { } public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } } }
    static class IOExtensions
    {
        public static string String(this BufferedStreamReader reader) { return reader.ReadToken(); }
        public static string[] StringArray(this BufferedStreamReader reader, int n) { var array = new string[n]; for (int i = 0; i < n; ++i) { array[i] = reader.ReadToken(); } return array; }
        public static int Int(this BufferedStreamReader reader) { return int.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static int[] IntArray(this BufferedStreamReader reader, int n) { var array = new int[n]; for (int i = 0; i < n; ++i) { array[i] = int.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static uint UnsignedInt(this BufferedStreamReader reader) { return uint.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static long Long(this BufferedStreamReader reader) { return long.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static long[] LongArray(this BufferedStreamReader reader, int n) { var array = new long[n]; for (int i = 0; i < n; ++i) { array[i] = long.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static ulong UnsignedLong(this BufferedStreamReader reader) { return ulong.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static double Double(this BufferedStreamReader reader) { return double.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static double[] DoubleArray(this BufferedStreamReader reader, int n) { var array = new double[n]; for (int i = 0; i < n; ++i) { array[i] = double.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static decimal Decimal(this BufferedStreamReader reader) { return decimal.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); }
        public static decimal[] DecimalArray(this BufferedStreamReader reader, int n) { var array = new decimal[n]; for (int i = 0; i < n; ++i) { array[i] = decimal.Parse(reader.ReadToken(), CultureInfo.InvariantCulture); } return array; }
        public static void ArrayLine<T>(this FormattedStreamWriter writer, T[] array, int n, string format = "{0}", string separator = " ") { for (int i = 0; i < n; ++i) { if (i > 0) writer.Write(separator); writer.Write(format, array[i]); } writer.WriteLine(); }
        public static void ArrayLine<T>(this FormattedStreamWriter writer, T[] array, string format = "{0}", string separator = " ") { writer.ArrayLine(array, array.Length, format, separator); }
    }
    partial class Solver
    {
        protected readonly BufferedStreamReader read;
        protected readonly FormattedStreamWriter write;
        protected readonly FormattedStreamWriter error;
        public Solver(BufferedStreamReader read, FormattedStreamWriter write, FormattedStreamWriter error) { this.read = read; this.write = write; this.error = error; }
        public static T[][] Create2DArray<T>(int dim1, int dim2) { var res = new T[dim1][]; for (int i = 0; i < dim1; ++i) res[i] = new T[dim2]; return res; }
        public static T[][][] Create3DArray<T>(int dim1, int dim2, int dim3) { var res = new T[dim1][][]; for (int i = 0; i < dim1; ++i) res[i] = Create2DArray<T>(dim2, dim3); return res; }
        public static T[][][][] Create4DArray<T>(int dim1, int dim2, int dim3, int dim4) { var res = new T[dim1][][][]; for (int i = 0; i < dim1; ++i) res[i] = Create3DArray<T>(dim2, dim3, dim4); return res; }
        public void Do() { Run(); }
    }
    static class Utils
    {
        public static void Swap<T>(ref T one, ref T second) { T tmp = one; one = second; second = tmp; }
    }
}
#endregion

namespace CC
{
    using System.Diagnostics;
    using System.Text;

    partial class Solver
    {
        public void Run()
        {            
            var n = read.Int();
            var l = new int[n];
            var r = new int[n];
            var left = new int[n];
            var right = new int[n];
            var taken = new bool[n];
            while (n-- > 0)
            {
                l[n] = read.Int();
                r[n] = read.Int();
                left[n] = right[n] = n;
            }
            long res0 = 0;
            long res1 = 0;
            Array.Sort(left, (x, y) => l[y].CompareTo(l[x]));
            Array.Sort(right, (x, y) => r[x].CompareTo(r[y]));
            int pos = 0;
            for (int i = 0, j = 0, dir = 0; i < left.Length && j < right.Length; dir = 1 - dir)
                if (dir == 1)
                {
                    while (i < left.Length && taken[left[i]])
                        ++i;
                    if (i < left.Length)
                    {
                        taken[left[i]] = true;
                        if (pos < l[left[i]] || pos > r[left[i]])
                        {
                            res0 += Math.Abs(pos - l[left[i]]);
                            pos = l[left[i]];
                        }
                    }
                }
                else
                {
                    while (j < right.Length && taken[right[j]])
                        ++j;
                    if (j < right.Length)
                    {
                        taken[right[j]] = true;
                        if (pos < l[right[j]] || pos > r[right[j]])
                        {
                            res0 += Math.Abs(pos - r[right[j]]);
                            pos = r[right[j]];
                        }
                    }
                }
            res0 += Math.Abs(pos);
            pos = 0;
            Array.Clear(taken, 0, taken.Length);
            for (int i = 0, j = 0, dir = 1; i < left.Length && j < right.Length; dir = 1 - dir)
                if (dir == 1)
                {
                    while (i < left.Length && taken[left[i]])
                        ++i;
                    if (i < left.Length)
                    {
                        taken[left[i]] = true;
                        if (pos < l[left[i]] || pos > r[left[i]])
                        {
                            res1 += Math.Abs(pos - l[left[i]]);
                            pos = l[left[i]];
                        }
                    }
                }
                else
                {
                    while (j < right.Length && taken[right[j]])
                        ++j;
                    if (j < right.Length)
                    {
                        taken[right[j]] = true;
                        if (pos < l[right[j]] || pos > r[right[j]])
                        {
                            res1 += Math.Abs(pos - r[right[j]]);
                            pos = r[right[j]];
                        }
                    }
                }
            res1 += Math.Abs(pos);
            write.WriteLine(Math.Max(res0, res1));
        }
    }
}

Measured memory_bytes: 21172