#include<iostream>
using namespace std;

int dp[3][2];

int max(int a, int b) {
	return (a > b) ? a : b;
}

int main() {
	int n, a, b, c, i;
	cin >> n;
	cin >> a >> b >> c;
	dp[0][0] = 0;
	dp[1][0] = a;
	dp[2][0] = b;

	for(i = 2; i <= n; i++) {
		// citeste linia urmatoare
		cin >> a >> b >> c;

		// calculeaza coloana 1 din dp
		dp[0][1] = max(dp[0][0], dp[1][0]);
		dp[1][1] = max(dp[0][0] + a, dp[2][0] + b);
		dp[2][1] = max(dp[0][0] + b, dp[2][0] + c);

		// copiaza coloana 1 in coloana 0
		dp[0][0] = dp[0][1];
		dp[1][0] = dp[1][1];
		dp[2][0] = dp[2][1];
	}

	cout << max(dp[1][0], dp[0][0]) << "\n";
	return 0;
}