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

namespace EDPC_C
{
    class Program
    {
        static void Main(string[] args)
        {
            new Program().Calc();
        }

        Scanner cin;

        int[,] _happiness, _totalHappiness;

        public Program() { }

        void Calc()
        {
            cin = new Scanner();

            int n = cin.nextInt();

            _happiness = new int[n, 3];
            _totalHappiness = new int[n + 1, 3];

            for (int firstDayChoice = 0; firstDayChoice < 3; ++firstDayChoice)
            {
                _totalHappiness[0, firstDayChoice] = _happiness[0, firstDayChoice] = cin.nextInt();
            }

            for (int day = 1; day < n; ++day)
            {
                for (int todayChoice = 0; todayChoice < 3; ++todayChoice)
                {
                    _happiness[day, todayChoice] = cin.nextInt();
                    int max = 0;

                    for (int yesterdayChoice = 0; yesterdayChoice < 3; ++yesterdayChoice)
                    {
                        if (yesterdayChoice == todayChoice) { continue; }

                        max = Math.Max(max, _totalHappiness[day - 1, yesterdayChoice] + _happiness[day, todayChoice]);
                    }

                    _totalHappiness[day, todayChoice] = max;
                }
            }

            int ans = 0;
            for (int i = 0; i < 3; ++i)
            {
                ans = Math.Max(ans, _totalHappiness[n - 1, i]);
            }

            Console.WriteLine(ans);
        }
    }

    class Scanner
    {
        string[] s;
        int i;

        char[] cs = new char[] { ' ' };

        public Scanner()
        {
            s = new string[0];
            i = 0;
        }

        public string next()
        {
            if (i < s.Length) return s[i++];
            string st = Console.ReadLine();
            while (st == "") st = Console.ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            if (s.Length == 0) return next();
            i = 0;
            return s[i++];
        }

        public int nextInt()
        {
            return int.Parse(next());
        }
        public int[] ArrayInt(int N, int add = 0)
        {
            int[] Array = new int[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt() + add;
            }
            return Array;
        }

        public long nextLong()
        {
            return long.Parse(next());
        }

        public long[] ArrayLong(int N, long add = 0)
        {
            long[] Array = new long[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong() + add;
            }
            return Array;
        }

        public double nextDouble()
        {
            return double.Parse(next());
        }


        public double[] ArrayDouble(int N, double add = 0)
        {
            double[] Array = new double[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextDouble() + add;
            }
            return Array;
        }
    }
}


Measured memory_bytes: 17348