//		HYSO SERIOUS? WHY SO SERIOUS                            RIOUS? WHY SO SERIOUS? WHYSO SERIO
//		 ERIOUS? WHY SO SERIOUS ? WHY                          WHY SO SERIOUS? WHY SOSERIOUSWHYS
//		       OSERIOUS? WHY SO SERIOU         SERIOUS        ERIOUS? WHY SO SERIOUS? WHYS
//		          WHY SO SERIOUS? WHY SOSERIOUS? WHYSOSERIOUS? WHY SO SERIOUS?WHY SO SE
//		           ERIOUS? WHY SO SERIOUS? WHY SO SERIOUS? WHY SO SERIOUS? WHY SOSERIO
//		           WHY SO SERIOUS? WHY SO SERIOUS? WHY SO SERIOUS? WHY SO SERIOUS? WH
//		            SERIOUS?WHYSO SERIOUS? WHY SO SERIOUS? WHY SO SERIOUS? WHYSO SE
//		              ?WHYSOSERIOUS?WHY SO SERIOUS? WHY SO SERIOUS?WHYSO SERIOUS?
//		                           OSERIOUS? WHY SO SERIOUS?WHYSOSER
//		                                 HYSOSERIOUS?WHYSOSERI
//		                                     SOSERIOUS?W
//		                                         SER
//		                                          W


#include 	<ext/pb_ds/assoc_container.hpp> 
#include 	<ext/pb_ds/tree_policy.hpp> 
#include 	<iostream>
#include 	<queue>
#include 	<tuple>
#include 	<vector>
#include	<bits/stdc++.h>
#include	<algorithm>
#include 	<cmath>
#include 	<map>
#include 	<string>
#include 	<iomanip> 
using 		namespace __gnu_pbds; 
using 		namespace std;
#define 	ll  long long int
#define		read(a) long long int a; cin>>a;
#define 	readstr(s) string s; cin>>s;
#define 	readc(c) char c; cin>>c;
#define 	readarr(a,l) long long int a[l]={0}; for(ll i=0;i<l;i++) cin>>a[i];
#define 	loop(i,a,b) for(ll i=a;i<b;i++)
#define 	rloop(i,a,b) for(ll i=a;i>b;i--)
#define 	loopitr(vec) for(auto it=vec.begin();it!=vec.end();it++)
#define 	ff first
#define 	ss second
#define 	readmtrx(i,j,a,b) ll arr[a][b]={0};for(ll i=0;i<a;i++)for(ll j=0;j<b;j++) cin>>arr[i][j];
#define 	v(pi) vector<ll>pi
#define 	all(a) a.begin(), a.end()
#define 	yes cout <<"YES"<<endl;
#define 	no cout <<"NO"<<endl;
#define 	sc(x) cout << (#x) << " is " << (x) << endl;
#define 	vp(pi) vector<pair<ll,ll>>pi
#define 	fast ios_base::sync_with_stdio(false);cin.tie(0);
#define 	pb(p) push_back(p)
#define 	mp make_pair
#define 	mi(lol) map<ll,ll>lol
#define 	fsort(vec) sort(vec.begin(),vec.end())
#define 	rsort(vec) sort(vec.begin(),vec.end(),compare)
#define 	Endl endl
#define 	ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> 
#define 	roundoff std::cout << std::setprecision(15)
#define 	inf 9223372036854775807
#define 	infn -9223372036854775807
#define 	pi 3.14159265358979323846
const 		int mod = 1e9+7; 
#define 	REVERSE(vec) reverse(vec.begin(),vec.end())


ll gcd (ll a, ll b) { return b ? gcd (b, a % b) : a; }
ll lcm (ll a, ll b) { return a / gcd(a, b) * b; }

//code start from here 
ll arr[100001][3];
ll flag=0;
ll a=0;
ll i=0;ll j=0;
ll dp[4][1000001];
ll vac(ll flag ,ll i){
	if(dp[flag][i]!=-1) return dp[flag][i];
	if(i==a)return 0;
	if(flag==0) {
		ll p= max(vac(2,i+1)+arr[i][1],vac(3,i+1)+arr[i][2]);
		p=max(p,vac(1,i+1)+arr[i][0]);
		return dp[0][i]=p;
	}
	if(flag==1) return dp[1][i]=max(vac(2,i+1)+arr[i][1],vac(3,i+1)+arr[i][2]);
	else if(flag==2) return dp[2][i]=max(vac(1,i+1)+arr[i][0],vac(3,i+1)+arr[i][2]);
	else if(flag==3) return dp[3][i]=max(vac(2,i+1)+arr[i][1],vac(1,i+1)+arr[i][0]);
}

int main() {
	fast;
	memset(dp,-1,sizeof(dp));
	cin>>a;
	loop(i,0,a){
		loop(j,0,3){
			read(t)
			arr[i][j]=t;
		}
	}
	cout<<vac(flag,i)<<endl;
	return 0;
}

//ends here 

Measured memory_bytes: 38528