//rohitaas_15
#include <bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,fma")
#define co(x) 						          cout<<x<<"\n";
#define ld 							             long double
#define ll                          long long
#define int                         ll
#define dd                          double
#define rohitaas_15();              ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define all(v) 						v.begin(),v.end()
#define f(a,b) 						for(int i=a;i<=b;i++)
#define f2(a,b) 					for(int j=a;j<=b;j++)
#define f3(a,b) 					for(int kk=a;kk<=b;kk++)
#define pb 							push_back
#define mp 							make_pair
#define pii							pair<ll,ll>
#define ff 							first
#define ss 							second
#define nl 							cout<<"\n"
#define lb(v,x) 					lower_bound(v.begin(),v.end(),x)
#define ub(v,x) 					upper_bound(v.begin(),v.end(),x)
#define pv(v,x,n) 					if(n!=0){f(x,n-1){cout<<v[i]<<" ";}cout<<endl;}
#define cn(v,x,n) 					f(x,n){cin>>v[i];}
#define M1 							1000000007
#define M2	 						998244353
#define con 						continue
#define maxv(v) 					*max_element(all(v));
#define minv(v) 					*min_element(all(v));
#define sumv(v) 					accumulate(all(v),0ll)
#define pf 							push_front
#define popb 						pop_back
#define popf 						pop_front
#define br 							break
#define rev(x)  					reverse(all(x))
#define vr 							vector<ll>
#define vvr							vector<vr>
#define vvvr 						vector<vvr>
#define vll 						vector<pii>
#define PI 							3.141592653
#define MLL 						map<ll,ll>
#define fbo 						find_by_order
#define ook 						order_of_key
#define printclock                  cerr<<"Time : "<<1000*(ld)clock()/(ld)CLOCKS_PER_SEC<<"ms\n";
#define debug1(a) 					cout<<#a<<" = "<<(a)<<endl;
#define debug2(a,b) 				cout<<#a<<" = "<<(a)<<", "<<#b<<" = "<<(b)<<endl
#define debug3(a,b,c)				cout<<#a<<" = "<<(a)<<", "<<#b<<" = "<<(b)<<", "<<#c<<" = "<<(c)<<endl
#define debug4(a,b,c,d) 			cout<<#a<<" = "<<(a)<<", "<<#b<<" = "<<(b)<<", "<<#c<<" = "<<(c)<<", "<<#d<<" = "<<(d)<<endl
mt19937 							rng(chrono::steady_clock::now().time_since_epoch().count());
void randomize(vr &in,ll x)					{f(0,in.size()-1)in[i]=rand()%x + 1;}
ll gcd(ll a, ll b)									{if(!b)return a;return gcd(b, a % b);}
ll lcm(ll a , ll b)									{return (a*b)/ gcd(a,b);}
ll modmul(ll a, ll b,ll mod)        { return ((a%mod) * (b%mod)) % mod;}
ll modadd(ll a , ll b,ll mod)       { return((a%mod)+(b%mod)+mod)%mod;}
ll modsub(ll a , ll b,ll mod)       {return((a%mod) - (b%mod) + mod)%mod;}
ll moduloMul(ll a,ll b,ll mod)			{ll res = 0;a %= mod;while (b){if (b & 1)res = (res + a) % mod;a = (2 * a) % mod;b >>= 1;}return res;}
ll power(ll x,ll y,ll p=LLONG_MAX)  {ll res = 1;x = x % p;while (y > 0){if (y & 1)res = (res*x) % p;y = y>>1;x = (x*x) % p;}return res;}ll XFEEA,YFEEA,GCDFEEA;
double power2(double x, ll y)       {double res = 1;while (y > 0){if (y & 1)res =(double) (res*x);y = y>>1;x =(double)(x*x);}return res;}
void extendedEuclidAlgo(ll a,ll b)  {if(b==0){XFEEA=1;YFEEA=0;GCDFEEA=a;return;}extendedEuclidAlgo(b,a%b);ll cx=YFEEA;ll cy=XFEEA-(a/b)*YFEEA;YFEEA=cy;XFEEA=cx;}
ll modInverse(ll n,ll m)            {extendedEuclidAlgo(n,m);return (XFEEA%m+m)%m;}
ll CmP(ll n, ll r, ll p=M1)         {if (r==0)return 1;ll fac[n+1];fac[0] = 1;for (ll i=1 ; i<=n; i++)fac[i] = fac[i-1]*i%p;return (fac[n]* modInverse(fac[r], p) % p *modInverse(fac[n-r], p) % p) % p;}
bool isSAFE(ll i,ll j,ll m,ll n)		{return (i>=1 && i<=m && j>=1 && j<=n);}
typedef                             tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> orderedset;

/*find_by_order(ll k){returns the iterator to the kth smallest element,start from 0,O(logn)}
order_of_key(ll k){returns the number of elements in the set which are strictly less than our k,O(logn)}*/

//vector<vr> g;
//vvr mat;
vector<vr> in;
ll n;
vvvr dp;
ll fun(ll i,ll prev)
{
	if(i==n+1)
	{
		return 0;
	}
	ll ans=-1;
	f2(1,3)
	{
		if(j!=prev)
		{
			if(dp[i][j][prev]==-1)
			dp[i][j][prev]=in[j][i]+fun(i+1,j);
		}
	}
	return max({dp[i][1][prev],dp[i][2][prev],dp[i][3][prev]});
}
void solve(){}
void ask(){}
signed main()
{
	rohitaas_15();
	ll t=1;
	//cin>>t;
	ll cases=t;
	while(t--)
	{
			cin>>n;
			in.resize(4,vr(n+1,0));
			dp.resize(n+1,vvr(4,vr(4,-1)));
			f(1,n)
			{
				ll a,b,c;cin>>a>>b>>c;
				in[1][i]=a;
				in[2][i]=b;
				in[3][i]=c;
			}
			co(fun(1,0));

			//pv(dp,1,dp.size());


	}

	//printclock;
}

	/*cout<<"Case #"<<cases-t<<": ";*/


Measured memory_bytes: 46048