#include <iostream>
#include <bits/stdc++.h>
using namespace std;

const int maxn = 1e5;
int n;
int a[4][maxn];
int dp[4][maxn];
int rec(int isk, int at){
    if(at == n){
        return 0;
    }
    if(dp[isk][at] != -1) {
        return dp[isk][at];
    }
    int rez = -1e8;
    for(int i = 1; i <= 3; i++){
        if(isk != i){
            rez = max(rez, rec(i, at + 1) + a[i][at]);
        }
    }
    return dp[isk][at] = rez;
}

int main()
{
    cin >> n;
    for(int i = 0; i < n; i++){
        for(int j = 1; j <= 3; j++){
            cin >> a[j][i];
        }
    }
    memset(dp, -1, sizeof dp);
    cout << rec(0, 0);

    return 0;
}