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



using namespace std;



vector<vector<int> > v;

int ans[100005][3];

queue<pair<int,pair<int,int> > >s;

int maior,a=0;



void dp(int i, int bloq, int sum) {

  if(ans[i-1][bloq]>sum)

    return;

  

  if (i>=v.size())

    maior = max(sum, maior);

  else {

    for (int j=0; j<3; j++) {

      if (bloq != j) {



        if(ans[i][j]==-1) {

          ans[i][j] = sum+v[i][j];

          s.push({sum+v[i][j],{i+1,j}});

        }

        else if (ans[i][j]<sum+v[i][j]) {

          ans[i][j] = sum+v[i][j];

          s.push({sum+v[i][j],{i+1,j}});

        }



        //dp(i+1, j, sum+v[i][j]);

      }

    }

  }

}



int main () {

  int n;

  cin>>n;

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

    int a,b,c;

    cin>>a>>b>>c;

    v.push_back({a,b,c});

  }



  maior=0;

  memset(ans, -1, sizeof(ans));

  for (int i=0; i<3; i++) {

    s.push({v[0][i],{1,i}});

    //dp(1, i, v[0][i]);

  }



  while(!s.empty()) {

    pair<int,pair<int,int> > aux = s.front();

    dp(aux.second.first, aux.second.second, aux.first);

    s.pop();

  }



  cout<<maior<<endl;



}




// Faster C++ solution for the same problem (measured speedup: 2.187176688972566x):
#include <iostream>

#include <bits/stdc++.h>

#define mod 998244353

typedef long long ll;



using namespace std;



void Fastio(){

    ios::sync_with_stdio(0);

    cin.tie(0);

    cout.tie(0);

}



ll fact[1000006], inv[1000006];



ll fp(ll base, ll exp)

{

    if (exp == 0)

        return 1;

    ll ans = fp(base, exp / 2);

    ans = (ans * ans) % mod;

    if (exp % 2 != 0)

        ans = (ans * (base % mod)) % mod;

    return ans;

}



void calcFacAndInv(ll n)

{

    fact[0] = inv[0] = 1;

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

    {

        fact[i] = (i * fact[i - 1]) ;

        inv[i] = fp(fact[i], mod - 2);

    }

}



ll ncr(ll n, ll r)

{

    return ((fact[n] * inv[r]) % mod * inv[n - r]) % mod;

}



ll npr(ll n, ll r)

{

    return (fact[n] * inv[n - r]) % mod;

}



long double  NCR(int n, int m){

    long double res = 1;

    m = min(m, n - m);

    for(int i = 0; i < m; i++){

        res = res * ( n - i) / (i + 1);

 }

    return res;

}

ll tol(string a){

    ll res=0;

    while(a[0]=='0'){

        a.erase(a.begin());

    }

    if(a=="")a="0";

    for(int i=0; i<a.size(); i++){

        res*=10; res+=a[i]-'0';

    }

    return res;

}

int check(string a, string b){

    for(int i=0; i<a.size(); i++){

        if(a[i]>b[i])return 1;

        if(b[i]>a[i])return -1;

    }

    return 0;

}

class data{

public:

    ll v,d,p;

    data(){}

    data(ll vv, ll dd, ll pp){

        v=vv;  d=dd; p=pp;

    }

};



int primeFactors(int n)

{

    ll c=0;

    while (n % 2 == 0)

    {

        c++;

        n = n/2;

    }

    for (int i = 3; i*i <= n; i = i + 2)

    {

        while (n % i == 0)

        {

            c++;

            n = n/i;

        }

    }

    if (n > 2)

        c++;

    return c;

}



int main()

{

    Fastio();

    int n; cin>>n;

    ll a[n],b[n],c[n];

    ll dp[n+1][5];

    memset(dp,0,sizeof(dp));

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

        cin>>a[i]>>b[i]>>c[i];

    }

    for(int i=n-1; i>=0; i--){

        for(int y=0; y<3; y++){

            ll res1,res2,res0;

            res0=res1=res2=-1e9;

            res0=dp[i+1][0]+a[i];

            res1=dp[i+1][1]+b[i];

            res2=dp[i+1][2]+c[i];

            if(y==0){

                dp[i][y]=max(res1,res2);

            }

            if(y==1){

                dp[i][y]=max(res0,res2);

            }

            if(y==2){

                dp[i][y]=max(res0,res1);

            }

        }

    }

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





    return 0;

}