#include <iostream>
#include <queue>
using namespace std;
int n;
int mat[100005][3];
int dp[100005][3];
int main(){
    cin >> n;
    for(int i = 0; i < n; i++) {
        cin >> mat[i][0] >> mat[i][1] >> mat[i][2];
        dp[i][0] = dp[i][1] = dp[i][2] = -2e9;
    }
    dp[0][0] = mat[0][0];
    dp[0][1] = mat[0][1];
    dp[0][2] = mat[0][2];

    for(int day = 0; day + 1 < n; day++) {
        for(int prev_activity = 0; prev_activity < 3; prev_activity++) {
            for(int next_activity = 0; next_activity < 3; next_activity++) {
                if(prev_activity != next_activity) {
                    dp[day + 1][next_activity] = max(dp[day + 1][next_activity], dp[day][prev_activity] + mat[day + 1][next_activity]);
                }
            }
        }
    }
    cout << max(dp[n - 1][0], max(dp[n - 1][1], dp[n - 1][2])) << endl;
    return 0;
}