#include <iostream>
#include <vector>
#define ll long long
#define vi vector<int>
#define vii vector<ll>
using namespace std;

void file_io()
{
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    file_io();
    ll n;
    cin >> n;
    vector<vii> a(n, vii(3));
    for (ll i = 0; i < n; i++)
    {
        for (ll j = 0; j < 3; j++)
        {
            cin >> a[i][j];
        }
    }
    vii dp(n, -1);
    ll tmp = -1;
    dp[0] = max(a[0][0], max(a[0][1], a[0][2]));
    if (dp[0] == a[0][0])
        tmp = 0;
    else if (dp[0] == a[0][1])
        tmp = 1;
    else
        tmp = 2;
    for (ll i = 1; i < n; i++)
    {
        ll tmp2 = -1;
        for (ll j = 0; j < 3; j++)
        {
            if (tmp == j)
                continue;
            if (dp[i] < dp[i - 1] + a[i][j])
            {
                tmp2 = j;
                dp[i] = dp[i - 1] + a[i][j];
            }
        }
        tmp = tmp2;
    }
    cout << dp[n - 1] << endl;
    return 0;
}