#include <cstdio>

using namespace std;

int  e[1000010][5], dp[1000010][5];
int n;

void citire()
{
    freopen ("points.in", "r", stdin);
    scanf("%d", &n);

    for (int i=1; i<=n; i++)
        for (int j=1; j<=3; j++)
            scanf ("%d", e[i]+j);
}

void initializare()
{
    for (int i=0;i<=n+1; i++)
        for (int j=0; j<=3; j++)
            dp[i][j]=-0x3f3f3f3;
}





int main()
{

    citire();
    initializare();
    dp[1][1]=0; dp[1][2]=0;
    for (int i=2; i<=n+1; i++)
    {
        if (dp[i][1]<dp[i-1][1])
            dp[i][1]=dp[i-1][1];
        if (dp[i][2]<dp[i-1][1])
            dp[i][2]=dp[i-1][1];
        if (dp[i][3]<dp[i-1][2]+e[i-1][2])
            dp[i][3]=dp[i-1][2]+e[i-1][2];
        if (dp[i][1]<dp[i-1][2]+e[i-1][1])
            dp[i][1]=dp[i-1][2]+e[i-1][1];
        if (dp[i][1]<dp[i-1][3]+e[i-1][2])
            dp[i][1]=dp[i-1][3]+e[i-1][2];
        if (dp[i][3]<dp[i-1][3]+e[i-1][3])
            dp[i][3]=dp[i-1][3]+e[i-1][3];
    }
fprintf (fopen("points.out", "w"), "%d\n", dp[n+1][1]);
    return 0;
}