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

 

#define pb push_back

#define fst first

#define snd second

#define INF 0x7fffffff

#define INFLL 0x7FFFFFFFFFFFFFFF

#define lenA(ar) sizeof(ar)/sizeof(*ar)

#define lenrows(mat) sizeof(mat)/sizeof(*mat)

#define lencols(mat) sizeof(*mat)/sizeof(**mat)

#define fill(a,c) memset(&a, c, sizeof(a))

#define fore(i,x,y) for(ll i=x;i<y;i++)

#define foreI(i,x,y) for(ll i=x-1;i>=y;i--)

#define max2(a,b) max(a, b)

#define max3(a,b,c) max2(max2(a,b),c)

#define min2(a,b) min(a, b)

#define min3(a,b,c) min2(min2(a,b),c)

#define MOD 1000000009

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

#define rall(x) (x).rbegin(), (x).rend()

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

 

typedef long long ll;

typedef unsigned long long ull;

 

using namespace std;

ll arr[100010][3];

ll dp[100010][3];

int n;

ll solve(int i, int j){

    if(i==n-1) return arr[i][j];

    ll &r = dp[i][j];

    if(r>-1) return r;

    ll a = 0; ll b = 0;ll c = 0; ll act=arr[i][j];

    if(j!=0) a=solve(i+1, 0)+act;

    if(j!=1) b=solve(i+1, 1)+act;

    if(j!=2) c=solve(i+1, 2)+act;

   return r=max3(a,b,c);

}

 

int main() {

     

    cin>>n;

    arr[n][3];

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

    fore(i,0,n){

        fore(j,0,3){

            cin>>arr[i][j];

        }

    }

 

    cout<<max3(solve(0,0),solve(0,1),solve(0,2))<<"\n";

 

    return 0;

}

// Faster C++ solution for the same problem (measured speedup: 3.330510690884122x):
// #pragma GCC optimize("Ofast,O3,unroll-loops")

// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")



#include <vector>

#include <list>

#include <map>

#include <set>

#include <deque>

#include <queue>

#include <stack>

#include <bitset>

#include <algorithm>

#include <functional>

#include <numeric>

#include <utility>

#include <iostream>

#include <sstream>

#include <iomanip>

#include <cstdio>

#include <cmath>

#include <cstdlib>

#include <cctype>

#include <string>

#include <cstring>

#include <cstdio>

#include <cmath>

#include <cstdlib>

#include <ctime>

#include <climits>

#include <complex>

#include <ext/pb_ds/assoc_container.hpp>

#include <ext/pb_ds/tree_policy.hpp>



using namespace __gnu_pbds;

using namespace std;



#define endl '\n'

#define hoise cerr<<"hoise - "<<__LINE__<<"\n"

#define tham getchar()

#define set0(ar) memset(ar, 0, sizeof ar)

#define setinf(ar) memset(ar, 126, sizeof ar)

#define vsort(v) sort(v.begin(), v.end())

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

#define FASTIO ios::sync_with_stdio(false);cin.tie(nullptr)



using ll = long long;

using pii = pair <int, int>;

using pll = pair <ll, ll>;

using vi = vector <int>;

using vl = vector <ll>;

using vpii = vector < pii >;

using vpll = vector < pll >;



const int LOG = 20;

const int N = (int)2e5+6;

const double PI = acos(-1.0);

const ll MOD = 1e9 + 7;

const int INF = 1e9;

const double EPS = 1e-6;

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

const int knight_x[8] = {2, 1, -1, -2, -2, -1, 2, 1}, knight_y[8] = {1, 2, 2, 1, -1, -2, -1, -2};



#define dbg(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }

void err(istream_iterator<string> it) {}

template<typename T, typename... Args>

void err(istream_iterator<string> it, T a, Args... args) {

    cerr << *it << " = " << a << " ";

    err(++it, args...);

    cout << endl;

}



int flipBit (int mask, int k) { return mask = mask ^ (1 << k); }

bool checkBit (int mask, int k) { return (mask >> k) & 1; }

int setBit (int mask, int k) { return mask = mask | (1 << k); }

int resetBit (int mask, int k) { if (checkBit (mask, k)) { mask = flipBit (mask, k); } return mask; }



inline void normal(ll &a) { a %= MOD; (a < 0) && (a += MOD); }

inline ll modMul(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); return (a * b) % MOD; }

inline ll modAdd(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); return (a + b) % MOD; }

inline ll modSub(ll a, ll b) { a %= MOD, b %= MOD; normal(a), normal(b); a -= b; normal(a); return a; }

inline ll modPow(ll b, ll p) { ll r = 1; while (p) { if (p & 1) r = modMul(r, b); b = modMul(b, b); p >>= 1; } return r; }

inline ll modInverse(ll a) { return modPow(a, MOD - 2); }

inline ll modDiv(ll a, ll b) { return modMul(a, modInverse(b)); }



template <typename T> using orderedSet = tree<T, null_type, greater<T>, rb_tree_tag, tree_order_statistics_node_update>;

template <typename T> using orderedSet1 = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;



bool equalTo ( double a, double b ) { if ( fabs ( a - b ) <= EPS ) return true;	else return false; }

bool notEqual ( double a, double b ){ if ( fabs ( a - b ) > EPS ) return true;	else return false; }

bool lessThan ( double a, double b ){ if ( a + EPS < b ) return true;	else return false; }

bool lessThanEqual ( double a, double b ){ if ( a < b + EPS ) return true;	else return false;}

bool greaterThan ( double a, double b ){ if ( a > b + EPS ) return true;	else return false;}

bool greaterThanEqual ( double a, double b ){ if ( a + EPS > b ) return true;	else return false;}



int kase;



/*--------------------------------------------------------------------------------------------------------------------------*/



void solution () {

	int n;

	cin >> n;

	vi a (n), b (n), c (n);

	vector <vector <int> > dp (n + 1, vector <int> (3, 0));

	

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

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

	}

	

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

		dp[i][0] = max (b[i] + dp[i + 1][1], c[i] + dp[i + 1][2]);

		dp[i][1] = max (a[i] + dp[i + 1][0], c[i] + dp[i + 1][2]);

		dp[i][2] = max (a[i] + dp[i + 1][0], b[i] + dp[i + 1][1]);

	}

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

}



int main() {

	FASTIO;

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

	int tc;

	// cin >> tc;

	tc = 1;

	

	while (tc--) {

		solution ();

	}

	

    return 0;

}



/*

 * check corner cases

 * be careful before submitting in Lightoj, SPOJ, UVA

*/