#include 
#include 
using namespace std;
int n;
int mat[100005][3];
int dp[100005][3];
int rec(int day, int prev_activity) {
    if(day == n) {
        return 0;
    }
    if(dp[day][prev_activity] != -1) {
        return dp[day][prev_activity];
    }
    int result = -2e9;
    for(int next_activity = 0; next_activity <= 2; next_activity++) {
        if(next_activity != prev_activity) {
            result = max(result, rec(day + 1, next_activity) + mat[day][prev_activity]);
        }
    }
    dp[day][prev_activity] = result;
    return result;
}
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] = -1;
    }
    int day1 = rec(0, 0);
    int day2 = rec(0, 1);
    int day3 = rec(0, 2);
    
    cout << max(day1, max(day2, day3)) << endl;
    return 0;
}