#include <stdio.h>
#include <stdlib.h>

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

int main()
{
    int dp[3][2];
	int n, a, b, c, i;
	scanf("%d",&n);
	scanf("%d %d %d",&a,&b,&c);
	dp[0][0] = 0;
	dp[1][0] = a;
	dp[2][0] = b;
	for(i = 2; i <= n; i++)
    {
		scanf("%d %d %d",&a,&b,&c);
		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);
		dp[0][0] = dp[0][1];
		dp[1][0] = dp[1][1];
		dp[2][0] = dp[2][1];
	}
	printf("%d",max(dp[1][0],dp[0][0]));
	return 0;
}