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

//#include <ext/pb_ds/tree_policy.hpp>

//#include <ext/pb_ds/assoc_container.hpp>

#define ll                  long long int

#define ull                 unsigned long long int

#define ld                  long double

#define fi                  first

#define se                  second

#define pb                  push_back

#define pbb                 pop_back

#define mp                  make_pair

#define pii     	        pair<int,int>

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

#define uniq(x)             x.erase(unique(x.begin(),x.end()),x.end())

#define mem(array, value)   memset(array, value, sizeof(array))

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

#define PI      	        2*acos(0.0)

#define INF     	        1e9

#define EPS     	        1e-8

#define line                cout << "\n==========\n"

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

using namespace std;

//using namespace __gnu_pbds;

//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> orderedSet; 



const int N = 1e5+9;

int ara[N][3];

int dp[N][3];

int n;



int call(int idx, int pre)

{

    if (idx >= n){

        return 0;

    }

    if (dp[idx][pre] != -1){

        return dp[idx][pre];

    }

    int res = 0;

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

        if (i != pre){

            res = max(res, call(idx+1, i) + ara[idx][i]);

        }

    } 

    return dp[idx][pre] = res;

}



int main ()

{

    #ifdef Lollipop

    //freopen ("input.txt", "r", stdin);

    //freopen ("output.txt", "w", stdout);

    #endif

    mem(dp, -1);

    cin >> n;

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

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

            cin >> ara[i][j];

        }

    }

    cout << max({call(1, 0) + ara[0][0], call(1, 1) + ara[0][1], call(1, 2) + ara[0][2]}) << endl;

    return 0;

}








// Faster C++ solution for the same problem (measured speedup: 2.2027730005662107x):
#include <bits/stdc++.h>

//#include <ext/pb_ds/tree_policy.hpp>

//#include <ext/pb_ds/assoc_container.hpp>

using namespace std;

//using namespace __gnu_pbds;

#define ll                  long long int

#define ull                 unsigned long long int

#define ld                  long double

#define fi                  first

#define se                  second

#define pb                  push_back

#define pbb                 pop_back

#define mp                  make_pair

#define popcount            __builtin_popcountll

#define pii     	        pair<int,int>

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

#define uniq(x)             x.erase(unique(x.begin(),x.end()),x.end())

#define mem(array, value)   memset(array, value, sizeof(array))

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

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

#define PI      	        2*acos(0.0)

#define INF     	        1e9

#define EPS     	        1e-8

#define line                cout << "\n==========\n"

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

#define trace(...)          __f( #__VA_ARGS__ , __VA_ARGS__ )

template <typename Arg1>

void __f(const char* name, Arg1&& arg1){

    cerr << name << " : " << arg1 << "\n";

}

template <typename Arg1, typename... Args>

void __f(const char* names, Arg1&& arg1, Args&&... args){

    const char* comma = strchr(names + 1, ',');

    cerr.write(names, comma - names) << " : " << arg1 << " , ";

    __f(comma + 1, args...);

}

//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> orderedSet;



//int dx[] = {1, -1, 0, 0},                  dy[] = {0, 0, 1, -1};                  // 4 Direction

//int dx[] = {1, -1, 0, 0, 1, 1, -1, -1},    dy[] = {0, 0, 1, -1, 1, -1, 1, -1};    // 8 Direction

//int dx[] = {1, -1, 1, -1, 2, 2, -2, -2},   dy[] = {2, 2, -2, -2, 1, -1, 1, -1};   // Knight Direction



inline ll gcd(ll a, ll b){

    a = abs(a);

    b = abs(b);

    while (b){

        a = a % b;

        swap (a, b);

    }

    return a;

}

inline ll power(ll a, ll p){

    ll res = 1, x = a;

    while (p){

        if (p & 1){

            res = (res * x);

        }

        x = (x * x);

        p >>= 1;

    }

    return res;

}

inline ll mulmod(ll a, ll p, ll m){

    ll res = 0, x = a%m;

    while (p){

        if (p & 1){

            res = (res + x) % m;

        }

        x = (x << 1) % m;

        p >>= 1;

    }

    return res;

}

inline ll bigmod(ll a, ll p, ll m){

    ll res = 1 % m, x = a % m;

    while (p){

        if (p & 1){

            res = (res * x) % m;

        }

        x = (x * x) % m;

        p >>= 1;

    }

    return res;

}



int main ()

{

    #ifdef Lollipop

    //freopen ("input.txt", "r", stdin);

    //freopen ("output.txt", "w", stdout);

    #endif

    int n;

    cin >> n;

    vector<int> dp(3);

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

        vector<int> c(3);

        vector<int> new_dp(3, 0);

        for (int& x: c){

            cin >> x;

        }

        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]+c[j]);

                }

            }

        }

        dp = new_dp;

    }

    cout << max({dp[0], dp[1], dp[2]}) << endl;

    return 0;

}