using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Numerics;
using static System.Math;
using static System.Array;
using static AtCoder.Tool;
using static AtCoder.CalcL;
namespace AtCoder
{
    class AC
    {
        //const int MOD = 1000000007;
        const int MOD = 998244353;
        const int INF = int.MaxValue / 2;
        const long SINF = long.MaxValue / 2;
        const double EPS = 1e-8;
        static readonly int[] dI = { 0, 1, 0, -1 };
        static readonly int[] dJ = { 1, 0, -1, 0 };
        static List<List<int>> G = new List<List<int>>();
        //static List<List<Edge>> G = new List<List<Edge>>();
        //static List<Edge> E = new List<Edge>();
        
        static void Main(string[] args)
        {
            //var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            //Console.SetOut(sw);
            var cin = new Scanner();

            int N = int.Parse(Console.ReadLine());
            var lm = new int[N];
            var rm = new int[N];
            var L = new List<Tuple<int, int>>();
            var R = new List<Tuple<int, int>>();
            for(var k = 0; k < N; k++)
            {
                var p = cin.ReadSplitInt();
                lm[k] = p[0];rm[k] = p[1];
                L.Add(new Tuple<int, int>(p[0], k));
                R.Add(new Tuple<int, int>(p[1], k));
            }
            L.Sort((x, y) => (y.Item1 - x.Item1));
            R.Sort();
            var used = new bool[N];
            long ans = 0;
            long ans2 = 0;
            int cur = 0;
            int cn = 0;
            int i = 0, j = 0;

            Func<int, int, int, int> move = (l, r, c) =>
            {
                if (l <= c && c <= r)
                {
                    return c;
                }
                if (c < l)
                {
                    return l;
                }
                return r;
            };
            while (true)
            {
                while (used[L[i].Item2]) i++;
                //Console.WriteLine(L[i].Item2);
                int nx = move(L[i].Item1, rm[L[i].Item2], cur);
                ans += Abs(cur - nx);
                cur = nx;
                used[L[i].Item2] = true;
                cn++;
                if (cn == N)
                {
                    ans += Abs(cur);
                    break;
                }
                while (used[R[j].Item2]) j++;
                //Console.WriteLine(R[j].Item2);
                nx = move(lm[R[j].Item2], R[j].Item1, cur);
                ans += Abs(cur - nx);
                cur = nx;
                used[R[j].Item2] = true;
                cn++;
                if (cn == N)
                {
                    ans += Abs(cur);
                    break;
                }
            }
            cur = cn = i = j = 0;
            Initialize(ref used, false);
            while (true)
            {
                while (used[R[j].Item2]) j++;
                //Console.WriteLine(R[j].Item2);
                int nx = move(lm[R[j].Item2], R[j].Item1, cur);
                ans2 += Abs(cur - nx);
                cur = nx;
                used[R[j].Item2] = true;
                cn++;
                if (cn == N)
                {
                    ans2 += Abs(cur);
                    break;
                }
                while (used[L[i].Item2]) i++;
                //Console.WriteLine(L[i].Item2);
                nx = move(L[i].Item1, rm[L[i].Item2], cur);
                ans2 += Abs(cur - nx);
                cur = nx;
                used[L[i].Item2] = true;
                cn++;
                if (cn == N)
                {
                    ans2 += Abs(cur);
                    break;
                }
            }
            //Console.WriteLine(ans);
            //Console.WriteLine(ans2);
            Console.WriteLine(Max(ans, ans2));
            //Console.Out.Flush();
        }
        struct Edge
        {
            public int from;

            public int to;
            public long dist;
            public Edge(int t, long c)
            {
                from = -1;
                to = t;
                dist = c;
            }
            public Edge(int f, int t, long c)
            {
                from = f;
                to = t;
                dist = c;
            }

        }
    }
    public class Scanner
    {
        public int[] ReadSplitInt()
        {
            return ConvertAll(Console.ReadLine().Split(), int.Parse);
        }
        public long[] ReadSplitLong()
        {
            return ConvertAll(Console.ReadLine().Split(), long.Parse);
        }
        public double[] ReadSplit_Double()
        {
            return ConvertAll(Console.ReadLine().Split(), double.Parse);
        }
    }
    public static class Tool
    {
        static public void Initialize<T>(ref T[] array, T initialvalue)
        {
            for (var i = 0; i < array.Length; i++)
            {
                array[i] = initialvalue;
            }
        }
        static public void Swap<T>(ref T a, ref T b)
        {
            T keep = a;
            a = b;
            b = keep;
        }

        static public void Display<T>(T[,] array2d, int n, int m)
        {
            for (var i = 0; i < n; i++)
            {
                for (var j = 0; j < m; j++)
                {
                    Console.Write($"{array2d[i, j]} ");
                }
                Console.WriteLine();
            }
        }

        static public long LPow(int a, int b)
        {
            return (long)Pow(a, b);
        }
    }
    static public class CalcI
    {
        public static int Gcd(int a, int b)
        {
            if (a * b == 0) { return Max(a, b); }
            return a % b == 0 ? b : Gcd(b, a % b);
        }
        public static int Lcm(int a, int b)
        {
            int g = Gcd(a, b);
            return a / g * b;
        }
        public static int Ceil(int n, int div)
        {
            return (n + div - 1) / div;
        }
    }
    static public class CalcL
    {
        public static long Gcd(long a, long b)
        {
            if (a * b == 0) { return Max(a, b); }
            return a % b == 0 ? b : Gcd(b, a % b);
        }
        public static long Lcm(long a, long b)
        {
            long g = Gcd(a, b);
            return a / g * b;
        }
        public static long Ceil(long n, long div)
        {
            return (n + div - 1) / div;
        }
    }
    class Modulo
    {
        private int M;
        private readonly long[] m_facs;
        public long Mul(long a, long b)
        {
            return ((a * b) % M);
        }
        public Modulo(long n, int m)
        {
            M = m;
            m_facs = new long[n + 1];
            m_facs[0] = 1;
            for (long i = 1; i <= n; ++i)
            {
                m_facs[i] = Mul(m_facs[i - 1], i);
            }
        }
        public long Fac(long n)
        {
            return m_facs[n];
        }
        public long Pow(long a, long m)
        {
            switch (m)
            {
                case 0:
                    return 1L;
                case 1:
                    return a;
                default:
                    long p1 = Pow(a, m / 2);
                    long p2 = Mul(p1, p1);
                    return ((m % 2) == 0) ? p2 : Mul(p2, a);
            }
        }
        public long Div(long a, long b)
        {
            return Mul(a, Pow(b, M - 2));
        }
        public long Ncr(long n, long r)
        {
            if (n < r) { return 0; }
            if (n == r) { return 1; }
            long res = Fac(n);
            res = Div(res, Fac(r));
            res = Div(res, Fac(n - r));
            return res;
        }
    }
}


Measured memory_bytes: 28644