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

using namespace std;



/*

#pragma GCC optimize("Ofast,no-stack-protector")

#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#pragma GCC optimize("unroll-loops")

*/



//************** StrAnge.R *********************



#define ll              long long int

#define ull             unsigned long long

#define ld              long double

#define lll             __int128

#define vi              vector<int>

#define vl              vector<ll>

#define vvi             vector<vector<int> >

#define pii             pair<int,int>

#define piii            pair<int,pair<int,int> >

#define pll             pair<ll,ll>

#define vii             vector<pii>

#define min_pq          priority_queue<int,vector<int>,greater<int> >



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

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

#define allr(s)         s.rbegin(),s.rend()

#define unq(c)          (sort(all(c)), c.resize(distance(c.begin(),unique(all(c)))))

#define get_pos(c,x)    (lower_bound(all(c),x)-c.begin())



#define MS0(v)          memset((v), 0, sizeof((v)))

#define MS1(v)          memset((v), -1, sizeof((v)))

#define LEN(v)          strlen(v)



#define MP              make_pair

#define pb              push_back

#define pob             pop_back

#define ff              first

#define ss              second

#define sc              scanf

#define pf              printf

#define endl            "\n"



#define intmx           INT_MAX

#define llmx            1llu<<61

#define PI              3.14159265358979323846264338327950L

#define MOD             1000000007

#define MAX             100010



#define gcd(a, b)           __gcd(a, b)

#define lcm(a, b)           ((a)*((b)/gcd(a,b)))



#define shuffle(v)          (random_shuffle(all(v)))

#define min_ele(v)          (*min_element(all(v)))

#define max_ele(v)          (*max_element(all(v)))

#define is_equal(x, y)      (abs(x-y)<eps)

#define cnt_ele(v, x)       (count(all(v), x))

#define sum_ele(v)          (accumulate(all(v),0))

#define pro_ele(v)          (accumulate(all(v),1, multiplies<int>()))

#define init_range(v, x)    (iota(all(v),x))

#define ran(a, b)           ((((rand() << 15) ^ rand()) % ((b) - (a) + 1)) + (a))



#define TEST_CASE           int ___T; cin>>___T; for(int cs=1;cs<=___T;cs++)

#define PRINT_CASE          cout << "Case " << cs << ": ";

#define PRINT_CASEN         cout << "Case " << cs << ": \n";



#define vpf(v)              for(int i=0;i<v.size();i++){cout<<v[i];if(i!=v.size()-1)cout<<" ";else cout<<"\n";}

#define vsc(v)              for(int i=0;i<v.size();i++)cin>>v[i];



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

#define ROF(i, a, b, stp)   for(int i = (a); i >= (b); i-=stp)



template<class T>inline bool read(T &x) {int c=getchar();int sgn=1;while(~c&&c<'0'||c>'9'){if(c=='-')sgn=-1;c=getchar();}for(x=0;~c&&'0'<=c&&c<='9';c=getchar())x=x*10+c-'0'; x*=sgn; return ~c;}

inline ll exp(ll a, ll p)               { if(p == 0) return 1; ll x = exp(a, p / 2) % MOD; x = (x * x) % MOD; if(p & 1) x = (x * (a % MOD)) % MOD; return x; }



inline int add(int a, int b) { a += b; if(a >= MOD) a -= MOD; return a; }

inline int sub(int a, int b) { a -= b; if(a < MOD) a += MOD; return a; }

inline int multi(ll a, ll b) { a *= b; if(a >= MOD) a %= MOD; return a; }



inline int on_bit(int N,int pos)    {return N = N | (1<<pos);}

inline int off_bit(int N,int pos)   {return N = N & ~(1<<pos);}

inline bool check_bit(ll N,int pos) {return (bool)(N & (1<<pos));}

#define on_bit_cnt(x)               (__builtin_popcount(x))



#define start_clock     clock_t tStart = clock()

#define end_clock       printf("\n>>Runtime: %.10fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC)



#define fastio          ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)

#define fileio          freopen("in.txt","r",stdin);freopen("out.txt","w",stdout)





//******************* my code starts here **********************************



int n, aa[100005], bb[100005], cc[100005];

int dp[100005][2][2][2];



int solve(int pos, int a, int b, int c) {

    if(pos > n) return 0;



    int &ret = dp[pos][a][b][c];

    if(ret != -1) return ret;



    int x = 0, y = 0, z = 0;

    if(a == 0) x = solve(pos+1, 1, 0, 0) + aa[pos];

    if(b == 0) y = solve(pos+1, 0, 1, 0) + bb[pos];

    if(c == 0) z = solve(pos+1, 0, 0, 1) + cc[pos];



    return ret = max(x, max(y, z));

}



int main() {



    cin >> n;

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

        cin >> aa[i] >> bb[i] >> cc[i];

    }



    MS1(dp);

    cout << solve(1, 0, 0, 0) << "\n";



    return 0;

}


// Faster C++ solution for the same problem (measured speedup: 4.228009106880011x):
#include <bits/stdc++.h>

using namespace std;





//************** StrAnge.R *********************



#define ll              long long int

#define ull             unsigned long long

#define ld              long double

#define lll             __int128

#define vi              vector<int>

#define vl              vector<ll>

#define vvi             vector<vector<int> >

#define pii             pair<int,int>

#define piii            pair<int,pair<int,int> >

#define pll             pair<ll,ll>

#define vii             vector<pii>

#define min_pq      priority_queue<int,vector<int>,greater<int> >



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

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

#define allr(s)         s.rbegin(),s.rend()

#define unq(c)          (sort(all(c)), c.resize(distance(c.begin(),unique(all(c)))))

#define get_pos(c,x)    (lower_bound(all(c),x)-c.begin())

#define ran(a, b)       ((((rand() << 15) ^ rand()) % ((b) - (a) + 1)) + (a))



#define MS0(v)          memset((v), 0, sizeof((v)))

#define MS1(v)          memset((v), -1, sizeof((v)))

#define LEN(v)          strlen(v)



#define MP              make_pair

#define pb              push_back

#define pob             pop_back

#define ff              first

#define ss              second

#define sc              scanf

#define pf              printf

#define endl            "\n"



#define LL              ({ll __LL; scanf("%lld",&__LL); __LL;})

#define II              ({int __II; scanf("%d",&__II); __II;})

#define CC              ({char __CC; scanf("%c",&__CC); __CC;})

#define DD              ({double __DD; scanf("%lf",&__DD); __DD;})



#define intmx           INT_MAX

#define llmx            1llu<<61

#define PI              3.14159265358979323846264338327950L

#define MOD             1000000007

#define MAX             100010



#define gcd(a, b)       __gcd(a, b)

#define lcm(a, b)       ((a)*((b)/gcd(a,b)))



#define shuffle(v)          (random_shuffle(all(v)))

#define min_ele(v)          (*min_element(all(v)))

#define max_ele(v)          (*max_element(all(v)))

#define is_equal(x, y)      (abs(x-y)<eps)

#define cnt_ele(v, x)       (count(all(v), x))

#define sum_ele(v)          (accumulate(all(v),0))

#define pro_ele(v)          (accumulate(all(v),1, multiplies<int>()))

#define init_range(v, x)    (iota(all(v),x))



#define TEST_CASE       int ___T; scanf("%d",&___T); for(int cs=1;cs<=___T;cs++)

#define PRINT_CASE      printf("Case %d: ", cs)

#define PRINT_CASEN      printf("Case %d: \n", cs)



#define vpf(v, len)     for(int ix=0;ix<len;ix++){pf("%d",v[ix]);if(ix!=len-1)pf(" ");else pf("\n");}

#define vsc(v, len)     for(int ix=0;ix<len;ix++)scanf("%d",&v[ix]);



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

#define ROF(i, a, b, stp)   for(int i = (a); i >= (b); i-=stp)



template<class T>inline bool read(T &x) {int c=getchar();int sgn=1;while(~c&&c<'0'||c>'9'){if(c=='-')sgn=-1;c=getchar();}for(x=0;~c&&'0'<=c&&c<='9';c=getchar())x=x*10+c-'0'; x*=sgn; return ~c;}

inline ll exp(ll a, ll p)               { if(p == 0) return 1; ll x = exp(a, p / 2) % MOD; x = (x * x) % MOD; if(p & 1) x = (x * (a % MOD)) % MOD; return x; }



inline int add(int a, int b) { a += b; if(a >= MOD) a -= MOD; return a; }

inline int sub(int a, int b) { a -= b; if(a < MOD) a += MOD; return a; }

inline int multi(ll a, ll b) { a *= b; if(a >= MOD) a %= MOD; return a; }



inline int on_bit(int N,int pos)    {return N = N | (1<<pos);}

inline int off_bit(int N,int pos)   {return N = N & ~(1<<pos);}

inline bool check_bit(ll N,int pos) {return (bool)(N & (1<<pos));}

#define on_bit_cnt(x)               (__builtin_popcount(x))



#define start_clock     clock_t tStart = clock()

#define end_clock       printf("\n>>Runtime: %.10fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC)



#define fastio          ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)

#define fileio          freopen("in.txt","r",stdin);freopen("out.txt","w",stdout)





//******************* my code starts here **********************************





int main() {

    

    int n = II;



    vi dp(3);

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



        vi ar(3); vsc(ar, 3);

        vi new_dp(3, 0);



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



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

                if(i != j) {



                    new_dp[j] = max(new_dp[j], dp[i]+ar[j]);

                }

            }

        }

        dp = new_dp;

    }

    printf("%d\n", max(dp[0], max(dp[1], dp[2])));



    return 0;

}