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

typedef long long ll;

using namespace std;

const int N = 2e5+10 , M = 5e5+10, OO = 0x3f3f3f3f ,  MOD = 1e9+7;

const double EPS = 1e-3;

#define M_PI 3.14159265358979323846

#define clr(arr,val) memset(arr , val , sizeof (arr))

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

#define rloop(i,n) for(int i = int(n)-1;i >= 0;i--)

#define range(i,a,b) for(int i = int(a);i <= int(b);i++)

#define pb push_back

#define F first

#define S second

#define all(v) ((v).begin()) , ((v).end())

#define sz(v)  ((int)((v).size()))

typedef pair <int,int> pii ;

typedef vector < pii > vii ;

typedef vector < int > vi;

int dx[]={1,0,-1,0};int dy[]={0,1,0,-1}; //4 Direction

//int dx[]={1,1,0,-1,-1,-1,0,1};int dy[]={0,1,1,1,0,-1,-1,-1};//8 direction

//int dx[]={2,1,-1,-2,-2,-1,1,2};int dy[]={1,2,2,1,-1,-2,-2,-1};//Knight Direction

//int dx[6]={2,1,-1,-2,-1,1};int dy[6]={0,1,1,0,-1,-1}; //Hexagonal Direction

//freopen("input.txt", "r", stdin);

//freopen("output.txt", "w", stdout);







int n,x;

int a[N],b[N],c[N];

ll dp[N][4];





ll solve(int idx, int preC){ //preColour = (1 : a) -- (2 : b) -- (3 : c) -- (0 : invalid)



    if(idx == n) return 0;



    ll& ret = dp[idx][preC];

    if(~ret) return ret;



    ret = -OO;

    if(preC != 1) ret = max(ret, solve(idx+1 , 1)+a[idx]);

    if(preC != 2) ret = max(ret, solve(idx+1 , 2)+b[idx]);

    if(preC != 3) ret = max(ret, solve(idx+1 , 3)+c[idx]);



    return ret;



}







int main(){





    //ios_base::sync_with_stdio(0);

    //cin.tie(0);cout.tie(0);





    scanf("%d",&n);

    for(int i = 0 ; i < n ; ++i)

        scanf("%d %d %d",a+i,b+i,c+i);



    memset(dp, -1 , sizeof dp);

    ll ans = solve(0 , 0);

    printf("%lld\n",ans);







    return 0;

}


// Faster C++ solution for the same problem (measured speedup: 7.552512793977701x):
#include<bits/stdc++.h>



#define  ll         long long

#define  llu        unsigned long long

#define  mod        1000000007

#define  pi         ((2.0)*acos(0.0))

#define  pb         push_back

#define  pf         push_front

#define  eb         emplace_back

#define  mp         make_pair

#define  all(x)     (x).begin(),(x).end()

#define  X          first

#define  Y          second



/*loop*/

#define  fr(i,m,n)   for(ll i=m;i<n;++i)



/*output shortcuts*/

#define  nl         "\n"

#define  Yes        cout<<"Yes\n"

#define  yes        cout<<"yes\n"

#define  YES        cout<<"YES\n"

#define  No         cout<<"No\n"

#define  no         cout<<"no\n"

#define  NO         cout<<"NO\n"



using namespace std;

int main()

{

    ios::sync_with_stdio(0);

    cin.tie(0);

    cout.tie(0);



    ll n;

    cin>>n;

    ll a[n][3];



    fr(i,0,n)

        fr(j,0,3)

            cin>>a[i][j];



    //ll r=1;

    ll dp[n][3]={-1};



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

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

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



    fr(r,1,n)

    {

    for(ll i=0;i<3 && r<n; i++)  // cur_row

    {

        for(ll j=0;j<3;j++) // pre_row

        {

            if(j==i)

                continue;

            dp[r][i]=max(dp[r][i], dp[r-1][j]+a[r][i] );

        }

    }

    }



    /*cout<<nl<<nl;

    fr(i,0,n)

        {

            fr(j,0,3)

            {cout<<dp[i][j]<<" ";}

            cout<<nl;

        }

    */

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



return 0;

}