#include<bits/stdc++.h>
using namespace std;
int n, a[100005], b[100005], c[100005], dp[100005][5][5], ans;
signed main() {
	cin >> n;
	for(int i = 1;i <= n;i ++) {
		cin >> a[i] >> b[i] >> c[i];
	}
	for(int i = 1;i <= n;i ++) {
		dp[i][0][0] = max(dp[i - 1][1][1], dp[i - 1][2][1]) + a[i];
		dp[i][1][0] = dp[i - 1][2][1] + b[i];
		dp[i][1][1] = dp[i - 1][0][0] + b[i];
		dp[i][2][1] = max(dp[i - 1][1][0], dp[i - 1][0][0]) + c[i];
	}
	cout << max(dp[n][0][0], max(dp[n][1][0], max(dp[n][1][1], dp[n][2][1]))) << endl;
}