#include <bits/stdc++.h>
using namespace std;
#define MODS 100005
#define MOD 1000000007
#define all(x) (x).begin(), (x).end()
#define ll long long int
#define ld long double
#define bigint int64_t
#define vll vector<ll>
#define vpll vector<pair<ll,ll>>
#define mp make_pair
#define pb push_back
#define test ll t;read(t);while(t--)
#define pll pair<ll,ll>
#define vvll vector<vector<ll>>
#define fst first
#define scd second
#define ins insert
#define line "\n"

#define forn(i,n) for(ll (i) = 0 ; (i) < (n) ; ++(i))
#define for1(i,n) for(ll (i) = 1 ; (i) <= (n) ; ++(i))
#define forr(i,n) for(ll (i) = (n)-1 ; (i)>=0 ; --(i))
#define forab(i,a,b,c) for(ll (i) = a ; (i) <= (b) ; (i)+=(c))

template <typename T>
void read(T &x){
    cin >> x;
}
template <typename T , typename T0>
void read(T &x,T0 &y){
    cin >> x >> y;
}

template <typename T , typename T0 , typename T1>
void read(T &x,T0 &y,T1 &z){
    cin >> x >> y >> z;
}

template <typename T , typename T0 , typename T1 , typename T2>
void read(T &x,T0 &y,T1 &z,T2 &w){
    cin >> x >> y >> z >> w;
}

template <typename T , typename T0>
void read(pair< T , T0 > &p){
    cin >> p.fst >>p.scd;
}

template <typename T>
void read(vector< T > &oneD,ll n){
    forn(i,n)
    {
        ll x;
        read(x);
        oneD.push_back(x);
    }
}

template <typename T>
void read(T oneD[] , ll n){
    for(ll i=0;i<n;i++){
        read(oneD[i]);
    }
}

template <typename T>
void write(T &x){

    cout << x << " ";
}

template <typename T , typename T0>
void write(T &x,T0 &y){
    cout << x << " " << y << "\n";
}

template <typename T , typename T0 , typename T1>
void write(T &x,T0 &y,T1 &z){
    cout << x << " " << y << " " << z << "\n";
}

template <typename T , typename T0 , typename T1 , typename T2>
void write(T &x,T0 &y,T1 &z,T2 &w){
    cout << x << " " << y << " " << z << " " << w << "\n";
}

template <typename T , typename T0>
void write(pair< T , T0 > &p){
    write(p.fst);
    write(p.scd);
    cout << line;
}

template <typename T>
void write(vector< T > &oneD,ll n){
    for(ll i=0;i<n;i++){
        cout<<oneD[i]<<" ";
    }
    cout << line;
}

template <typename T>
void write(T oneD[] ,int n){
    for(ll i=0;i<n;i++){
        write(oneD[i]);
    }
    cout <<line;
}

template <typename T , typename T0>
void write(map< T , T0 > &mpp){
    for(auto it : mpp){
        write(it.fst);
        cout << ": ";
        write(it.scd);
        cout << "\n";
    }
    cout<<line;
}
void write(vvll rc,ll n,ll m)
{
    forn(i,n)
    {
        forn(j,m)
        {
            cout<<rc[i][j]<<" ";
        }
        cout<<line;
    }
}
ll maxl(ll a,ll b)
{
    return (a>b)?a:b;
}
void solve()
{
    ll n;
    read(n);
    vvll arr(3,vll(n,0));
    vvll store(3,vll(n,0));
    ll trap=0;
    forn(i,n)
    {
        forn(j,3)
        {
            read(arr[j][i]);
            trap=maxl(trap,arr[j][i]);
        }
    }
    if(n==1)
    {
        cout<<trap;
        return;
    }
    ll v1=0,v2=0;
    forn(i,n-1)
    {
        v1=maxl(arr[0][i]+arr[1][i+1],arr[1][i]);
        v2=maxl(arr[2][i]+arr[1][i+1],arr[1][i]);
        store[1][i+1]=maxl(v1,v2);

        v1=maxl(arr[1][i]+arr[0][i+1],arr[0][i]);
        v2=maxl(arr[2][i]+arr[0][i+1],arr[0][i]);
        store[0][i+1]=maxl(v1,v2);

        v1=maxl(arr[1][i]+arr[2][i+1],arr[2][i]);
        v2=maxl(arr[0][i]+arr[2][i+1],arr[2][i]);
        store[2][i+1]=maxl(v1,v2);

        arr[0][i+1]=store[0][i+1];
        arr[1][i+1]=store[1][i+1];
        arr[2][i+1]=store[2][i+1];
    }
    v1=0;
    forn(i,3)
    {
        v1=maxl(v1,store[i][n-1]);
    }
    cout<<v1;
}
int main() {
   
ios_base::sync_with_stdio(false);
cin.tie(NULL);
//*******************************************************//
solve();

return 0;
}




Measured memory_bytes: 5752