// Slower C++ solution:
#include <iostream>

#include <set>

#include <queue>

#include <vector>

#include <string>

#include <math.h>

#include <cmath>

#include <map>

#include <unordered_set>

#include <unordered_map>

#include <stack>

#include <algorithm>

#include <stdio.h>

#include <cstring>                    

#include <sstream>

#include <numeric>

#include <assert.h>



using namespace std;



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

#define VI    vector<int>

#define VLL    vector<ll>

#define VPI    vector<pair<int,int>>

#define VII    vector<VI>

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

#define SORT(v)    sort(all(v))

#define ll    long long

#define ull unsigned long long

#define scni(x)    scanf("%d",&x)           

#define scnll(x)    scanf("%lld",&x)        

#define scnd(x)    scanf("%lf",&x)          

#define prnti(x)    printf("%d\n",x)        

#define prntll(x)    printf("%lld",x)       

#define prntd(x)    printf("%.9lf",x)        

#define sz(x)  x.size()

#define pp push_back

#define P pair<int , int>

#define mp make_pair



const double EPS = 1e-9;

const double PI = 3.14159265359;



//  O( n * log(log(n)) )

vector<ll> primes;

void GeneratingPrimes(int top){

    vector<bool> p (top+1 , 1);

//    vector<ll> primes;

    p[0] = p[1] = 0;



    for(int i = 2; i <= sqrt(top) ; i++){

        if(p[i]){

            for(int j = i*i ; j <= top ; j+=i){

                p[j]=0;

            }

        }

    }

    lop(i , top+1)

        if(p[i])primes.push_back(i);

//    return primes;

}



ll gcd(ll a ,ll b){return (b==0)?a : gcd(b , a%b);}

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

void EXTgcd(ll a , ll b , ll & x0 , ll & y0){

    if(b==0){ x0 =1 , y0 = 0; return; }

    EXTgcd( b , a%b , x0 , y0 );

    ll x1 = y0;

    ll y1 = x0 - (a/b) * (y0);



	y1 = y1;

    x0 = x1;

    y0 = y1;

}



long long power(long long n, long long p , ll mod) {

    if (!p)

        return 1;

    long long ans = 1;

    while (p > 1) {

        if (p & 1)

            ans = (ans * n) % mod;

        n = (n * n) % mod;

        p /= 2;

    }

    return (ans * n) % mod;

}



double dist(double a , double b , double x, double y){ return sqrt( pow( a-x ,2) + pow( b-y ,2) ); }

double dist3(double a , double b , double c , double x , double y ,double z ){ return sqrt( pow( a-x ,2) + pow( b-y ,2) + pow( c-z ,2)); }



int xadd[9]= { 1 , -1 , 0 , 1 , -1 , 0 , 1 , -1 , 0 };

int yadd[9]= { 1 , -1 , 0 ,-1 ,  0 , 1 , 0 ,  1, -1 };



int xx[4]={0 , 1 , 0 , -1};

int yy[4]={1 , 0 , -1 , 0};



// string digits[]= {"1110111", "0010010", "1011101", "1011011", "0111010", "1101011", "1101111", "1010010", "1111111", "1111011"};



#define no  { cout<<"NO\n";  }

#define yes { cout<<"YES\n"; }

#define _1  { cout<<"-1\n";  }



ll const N = 1e5 + 10;

ll const INF = 1e18;

ll const mod = 1000000007;



///////////////////////////////////////////////////////////////////



ll n, a[N],b[N],c[N] , memo[N][3] , ans;



ll solve(int idx, int lt){

	if(idx==n)return 0;



	ll &ret = memo[idx][lt];

	if(~ret)return ret;



	if(lt==0){

		ret = max(solve(idx+1, 1)+b[idx], solve(idx+1, 2)+c[idx]);

	}

	if(lt==1){

		ret = max(solve(idx+1, 0)+a[idx], solve(idx+1, 2)+c[idx]);

	}

	if(lt==2){

		ret = max(solve(idx+1, 1)+b[idx], solve(idx+1, 0)+a[idx]);

	}

	return ret;

}



int main(){

	cin >> n;

	lop(i,n){

		scnll(a[i]), scnll(b[i]), scnll(c[i]);

	}



	memset(memo,-1,sizeof memo);

	ans = solve(1, 0)+a[0];

	ans = max(ans, solve(1, 1)+b[0]);

	ans = max(ans, solve(1, 2)+c[0]);



	cout << ans;

return 0;}

// Faster C++ solution for the same problem (measured speedup: 3.3813702208956165x):
#include <iostream>

#include <set>

#include <queue>

#include <vector>

#include <string>

#include <math.h>

#include <cmath>

#include <map>

#include <unordered_set>

#include <unordered_map>

#include <stack>

#include <algorithm>

#include <stdio.h>

#include <cstring>                    

#include <sstream>

#include <numeric>

#include <assert.h>



using namespace std;



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

#define VI    vector<int>

#define VLL    vector<ll>

#define VPI    vector<pair<int,int>>

#define VII    vector<VI>

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

#define SORT(v)    sort(all(v))

#define ll    long long

#define ull unsigned long long

#define scni(x)    scanf("%d",&x)           

#define scnll(x)    scanf("%lld",&x)        

#define scnd(x)    scanf("%lf",&x)          

#define prnti(x)    printf("%d\n",x)        

#define prntll(x)    printf("%lld",x)       

#define prntd(x)    printf("%.9lf",x)        

#define sz(x)  x.size()

#define pp push_back

#define P pair<int , int>

#define mp make_pair



const double EPS = 1e-9;

const double PI = 3.14159265359;



//  O( n * log(log(n)) )

vector<ll> primes;

void GeneratingPrimes(int top){

    vector<bool> p (top+1 , 1);

//    vector<ll> primes;

    p[0] = p[1] = 0;



    for(int i = 2; i <= sqrt(top) ; i++){

        if(p[i]){

            for(int j = i*i ; j <= top ; j+=i){

                p[j]=0;

            }

        }

    }

    lop(i , top+1)

        if(p[i])primes.push_back(i);

//    return primes;

}



ll gcd(ll a ,ll b){return (b==0)?a : gcd(b , a%b);}

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

void EXTgcd(ll a , ll b , ll & x0 , ll & y0){

    if(b==0){ x0 =1 , y0 = 0; return; }

    EXTgcd( b , a%b , x0 , y0 );

    ll x1 = y0;

    ll y1 = x0 - (a/b) * (y0);



	y1 = y1;

    x0 = x1;

    y0 = y1;

}



long long power(long long n, long long p , ll mod) {

    if (!p)

        return 1;

    long long ans = 1;

    while (p > 1) {

        if (p & 1)

            ans = (ans * n) % mod;

        n = (n * n) % mod;

        p /= 2;

    }

    return (ans * n) % mod;

}



double dist(double a , double b , double x, double y){ return sqrt( pow( a-x ,2) + pow( b-y ,2) ); }

double dist3(double a , double b , double c , double x , double y ,double z ){ return sqrt( pow( a-x ,2) + pow( b-y ,2) + pow( c-z ,2)); }



int xadd[9]= { 1 , -1 , 0 , 1 , -1 , 0 , 1 , -1 , 0 };

int yadd[9]= { 1 , -1 , 0 ,-1 ,  0 , 1 , 0 ,  1, -1 };



int xx[4]={0 , 1 , 0 , -1};

int yy[4]={1 , 0 , -1 , 0};



// string digits[]= {"1110111", "0010010", "1011101", "1011011", "0111010", "1101011", "1101111", "1010010", "1111111", "1111011"};



#define no  { cout<<"NO\n";  }

#define yes { cout<<"YES\n"; }

#define _1  { cout<<"-1\n";  }



ll const N = 1e5 + 10;

ll const INF = 1e18;

ll const mod = 1000000007;



///////////////////////////////////////////////////////////////////



ll n, a[N][3], dp[N][3];





int main(){

	cin >> n;

	lop(i,n){

		lop(j,3)scnll(a[i][j]);

	}

	lop(i,3)dp[0][i] = a[0][i];



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

		lop(j,3){

			lop(k,3)if(k!=j)dp[i][j] = max(dp[i][j], dp[i-1][k]+a[i][j]);

		}

	}



	ll ans=0;

	lop(i,3)ans=max(ans, dp[n-1][i]);

	cout << ans;

return 0;}