// Slower C++ solution:
#include <bits/stdc++.h>

using namespace std;

#define N (int)2e5

int n,a[N],b[N],c[N],memo[N][10];



// a = 0, b = 1, c = 2

int dp(int curr , int last) {

    if (curr > n) return 0;

    int &sol = memo[curr][last];

    if (sol != -1) return sol;

    if (last == 0) {

        sol = max(

            dp(curr + 1 , 1) + b[curr] ,

            dp(curr + 1 , 2) + c[curr]

        );

    } else if (last == 1) {

        sol = max(

            dp(curr + 1 , 0) + a[curr] ,

            dp(curr + 1 , 2) + c[curr]

        );

    } else {

        sol = max(

            dp(curr + 1 , 0) + a[curr] ,

            dp(curr + 1 , 1) + b[curr]

        );

    }

    return sol;

}



int main() {

    scanf("%d" , &n);

    for (int i = 1 ; i <= n ; i++)

        scanf("%d%d%d" , &a[i] , &b[i] , &c[i]);

    memset (memo , -1 , sizeof memo);

    printf("%d\n" , max(dp(2 , 0) + a[1] , max(dp(2 , 1) + b[1] , dp(2 , 2) + c[1])));

}


// Faster C++ solution for the same problem (measured speedup: 9.37117453349693x):
/* In the name of ALLAH */

#include<bits/stdc++.h>

#include<iostream>

#include<vector>

#include<string>



// MAXIMUM and MINIMUM elements

#define mx_ari(a)   *max_element(a , a+sizeof(a)/4)

#define mn_ari(a)   *min_element(a , a+sizeof(a)/4)

#define mx_arl(a)   *max_element(a , a+sizeof(a)/8)

#define mn_arl(a)   *min_element(a , a+sizeof(a)/8)

#define mx_vec(v)   *max_element(v.begin() , v.end())

#define mn_vec(v)   *min_element(v.begin() , v.end())

// COUNT the occurence of an element

#define cnt_ari(a,b)   count(a , a+sizeof(a)/4 , b)

#define cnt_arl(a,b)   count(a , a+sizeof(a)/8 , b)

#define cnt_vec(v,b)   count(v.begin() , v.end() , b)

// INPUTs

#define sci(a)        scanf("%d",&a)

#define scii(a,b)     scanf("%d %d",&a,&b)

#define sciii(a,b,c)  scanf("%d %d %d",&a,&b,&c)

#define scl(a)        scanf("%lld",&a)

#define scll(a,b)     scanf("%lld %lld",&a,&b)

#define sclll(a,b,c)  scanf("%lld %lld %lld",&a,&b,&c)

#define scf(a)        scanf("%f",&a)

#define scff(a,b)     scanf("%f %f",&a,&b)

#define scfff(a,b,c)  scanf("%f %f %f",&a,&b,&c)

#define scd(a)        scanf("%ld",&a)

#define scdd(a,b)     scanf("%lf %lf",&a,&b)

#define scddd(a,b,c)  scanf("%lf %lf %lf",&a,&b,&c)

// OUTPUTs

#define pri(a)        printf("%d ",a)

#define prii(a,b)     printf("%d %d ",a,b)

#define priii(a,b,c)  printf("%d %d %d ",a,b,c)

#define prl(a)        printf("%lld ",a)

#define prll(a,b)     printf("%lld %lld ",a,b)

#define prlll(a,b,c)  printf("%lld %lld %lld ",a,b,c)

#define prd(a)        printf("%.4lf ",a)

#define prdd(a,b)     printf("%.4lf %.4lf ",a,b)

#define prddd(a,b,c)  printf("%.4lf %.4lf %.4lf ",a,b,c)

#define prf(a)        printf("%.4f ",a)

#define prff(a,b)     printf("%.4f %.4f ",a,b)

#define prfff(a,b,c)  printf("%.4f %.4f %.4f ",a,b,c)

// LOOPs

#define foi(i,n)      for(int i=0;i<n;i++)

#define fol(i,n)      for(long long int i=0;i<n;i++)

#define fod(i,n)      for(double i=0;i<n;i++)

#define fof(i,n)      for(float i=0;i<n;i++)

// NEWLINEs

#define nwl           << "\n"

#define nl            printf("\n");

// PAIRs and PUSHbacks

#define mp            make_pair

#define pb            emplace_back

// IMPORTANTs

#define ll          long long

#define ull         unsigned long long int

#define mod         1000000007

#define lcm(a,b)     (a*b) / __gcd(a,b)



using namespace std;













int main()

{

   ll n; cin >> n;

   ll dp[n][3];

   ll a[n][3];



   fol(i,n){

      fol(j,3){

         cin >> a[i][j];

      }

   }

   

   dp[0][0] = a[0][0];

   dp[0][1] = a[0][1];

   dp[0][2] = a[0][2];



   for(ll i=1;i<n;i++){

      dp[i][0] = a[i][0] + max(dp[i-1][1] , dp[i-1][2]);

      dp[i][1] = a[i][1] + max(dp[i-1][0] , dp[i-1][2]);

      dp[i][2] = a[i][2] + max(dp[i-1][1] , dp[i-1][0]);

   }



   cout << max(dp[n-1][0] , max(dp[n-1][1] , dp[n-1][2]));



   return 0;

}