using EducationalDPContest.Questions;
using EducationalDPContest.Extensions;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace EducationalDPContest.Questions
{
    public class QuestionC : AtCoderQuestionBase
    {
        public override IEnumerable<object> Solve(TextReader inputStream)
        {
            int n = inputStream.ReadInt();
            var dp = new int[n, 3];
            Clear(dp);

            var abc = inputStream.ReadIntArray();
            for (int i = 0; i < 3; i++)
            {
                dp[0, i] = abc[i];
            }

            for (int i = 1; i < n; i++)
            {
                abc = inputStream.ReadIntArray();
                dp[i, 0] = Math.Max(dp[i - 1, 1], dp[i - 1, 2]) + abc[0];   // 前日にBかC、当日にA
                dp[i, 1] = Math.Max(dp[i - 1, 0], dp[i - 1, 2]) + abc[1];   // 前日にAかC、当日にB
                dp[i, 2] = Math.Max(dp[i - 1, 0], dp[i - 1, 1]) + abc[2];   // 前日にAかB、当日にC
            }

            yield return Math.Max(dp[n - 1, 0], Math.Max(dp[n - 1, 1], dp[n - 1, 2]));
        }

        void Clear(int[,] array)
        {
            for (int i = 0; i < array.GetLength(0); i++)
            {
                for (int j = 0; j < array.GetLength(1); j++)
                {
                    array[i, j] = int.MinValue;
                }
            }
        }
    }
}


namespace EducationalDPContest
{
    class Program
    {
        static void Main(string[] args)
        {
            IAtCoderQuestion question = new QuestionC();    // 問題に合わせて書き換え
            var answers = question.Solve(Console.In);
            foreach (var answer in answers)
            {
                Console.WriteLine(answer);
            }
        }
    }
}

#region Base Classes

namespace EducationalDPContest.Questions
{

    public interface IAtCoderQuestion
    {
        IEnumerable<object> Solve(string input);
        IEnumerable<object> Solve(TextReader inputStream);
    }

    public abstract class AtCoderQuestionBase : IAtCoderQuestion
    {
        public IEnumerable<object> Solve(string input)
        {
            var stream = new MemoryStream(Encoding.Unicode.GetBytes(input));
            var reader = new StreamReader(stream, Encoding.Unicode);

            return Solve(reader);
        }

        public abstract IEnumerable<object> Solve(TextReader inputStream);
    }

}

#endregion

#region Extensions

namespace EducationalDPContest.Extensions
{
    internal static class TextReaderExtensions
    {
        internal static int ReadInt(this TextReader reader) => int.Parse(ReadString(reader));
        internal static long ReadLong(this TextReader reader) => long.Parse(ReadString(reader));
        internal static double ReadDouble(this TextReader reader) => double.Parse(ReadString(reader));
        internal static string ReadString(this TextReader reader) => reader.ReadLine();

        internal static int[] ReadIntArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(int.Parse).ToArray();
        internal static long[] ReadLongArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(long.Parse).ToArray();
        internal static double[] ReadDoubleArray(this TextReader reader, char separator = ' ') => ReadStringArray(reader, separator).Select(double.Parse).ToArray();
        internal static string[] ReadStringArray(this TextReader reader, char separator = ' ') => reader.ReadLine().Split(separator);
    }
}

#endregion

Measured memory_bytes: 18400