// Slower C++ solution:
//#include <bits/stdc++.h>

#include <algorithm>

#include <iostream>

#include <iomanip>

#include <cstdio>

#include <cstdlib>

#include <cmath>

#include <cstring>

#include <vector>

#include <string>

#include <climits>

#include <map>

#include <set>

#include <stack>

#include <queue>

#include <deque>

#include <stdio.h>

//#define int long long

using namespace std;

#define loop(n) for(int i=0;i<n;i++)

#define endl '\n'

#define OnlineJudgec

#define F first

#define S second

#define  precision(n)  cout << fixed << setprecision(n)

#define clr(v,d ) memset(v, d, sizeof(v))

typedef long long ll;

typedef vector<int> vi;

void init()

{

    cin.tie(0);

    cin.sync_with_stdio(0);

    cout.tie(0);

    #ifdef OnlineJudge

    freopen("input.txt","r",stdin);

    freopen("output.txt","w",stdout);

    #endif

}

ll S(ll x){ll s = 0;while(x){s += x % 10;x /= 10;}return s;} /// sum of digits.

ll powe(ll a , ll n){if(n == 1)return a;return a * powe(a ,n-1);}

ll com(int n,int m){ll z = 1;for(int i = 0; i < m;i++){z = z * ( n - i) / (i + 1) ;}return z;}

int dx[] = {1,-1,0,0};

int dy[] = {0,0,1,-1};

int dr[] = {0,0,0,1,1,1,-1,-1,-1};

int dc[] ={-1,0,1,-1,0,1,-1,0,1};

/// <<------------------------------------------------------------------------------>>

const int mx = 100009;

int n , k;

int arr[mx][4];

int dp[mx][4];

int solve(int idx , int last)

{

     if(idx == n)return 0;

     int &ret = dp[idx][last];

     if(~ret) return ret;

     int A = 0 ,B = 0 ,C = 0;

     if(last != 0)

        A = solve(idx+1 , 0) + arr[idx][0];

     if(last != 1)

        B = solve(idx+1 , 1) + arr[idx][1];

     if(last != 2)

        C = solve(idx+1 , 2) + arr[idx][2];

     return ret = max(A,max(B,C));

}

/// <<------------------------------------------------------------------------------>>

int main()

{

    init();

    cin >> n;

    for(int i = 0 ;i < n;i++)

    {

        cin >> arr[i][0] >> arr[i][1] >> arr[i][2];

    }

    clr(dp,-1);

    cout<<solve(0,3);

}


// Faster C++ solution for the same problem (measured speedup: 2.5752272890826666x):
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define fast ios_base::sync_with_stdio(false),cin.tie(NULL)

#define x first

#define y second



vector<vector<int>> dp, arr;

int main() {

    fast;

    int n;

    cin>>n;

    arr.resize(n);

    dp.resize(n);

    for (int i = 0; i <n; ++i) {

        arr[i].resize(3);

        dp[i].resize(3);

        for (int j = 0; j < 3; ++j) {

            cin>>arr[i][j];

            dp[i][j] = -1;

        }

    }

    for (int i = n - 1; i >= 0; i--) {

        for (int j = 0; j < 3; ++j) {

            if(i == n-1)

            {

                dp[i][j] = arr[i][j];

            } else{

                int temp, max = 0;

                for (int k = 0; k < 3; ++k) {

                    if(k == j)

                        continue;

                    temp = dp[i + 1][k];

                    if(temp > max)

                        max = temp;

                }

                dp[i][j] = max + arr[i][j];

            }

        }

    }

    sort(dp[0].begin(), dp[0].end());

    cout<<dp[0][2];

}