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



using namespace std;

typedef long long int lli;



lli n, a[100005], b[100005], c[100005];



lli dp[100005][4];



lli solve(lli i, lli last){

    if(i == n) return dp[i][last] = 0;

    if(dp[i][last] != -1) return dp[i][last];

    lli ans1, ans2, ans3;

    ans1 = ans2 = ans3 = LONG_LONG_MIN;

    if(last != 1) ans1 = a[i] + solve(i+1, 1);

    if(last != 2) ans2 = b[i] + solve(i+1, 2);

    if(last != 3) ans3 = c[i] + solve(i+1, 3);



    return dp[i][last] = max(ans1, max(ans2, ans3));

}





int main(){

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

    int T=1, cs=1;

    //scanf("%d", &T);

    while(T--){

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

        scanf("%lld", &n);

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

            scanf("%lld %lld %lld", &a[i], &b[i], &c[i]);

        }

        printf("%lld\n", solve(0, 0));



    }



    return 0;

}

// Faster C++ solution for the same problem (measured speedup: 4.19746903514317x):
#include<bits/stdc++.h>

using namespace std;

typedef		long long       ll;

typedef         long double      dl;

typedef     unsigned long long  ull;

#define		pb              push_back

#define		PB              pop_back

#define		nn              "\n"

#define     O_O             ios_base::sync_with_stdio(false); cin.tie(NULL)

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

#define		zz(v)           (ll)v.size()

#define		ss              ' '

#define	       MEM(a,b)         memset(a,(b),sizeof(a))

#define	       CLR(p)           memset(p,0,sizeof(p))

#define f0(i,b) for(int i=0;i<(b);i++)

#define f1(i,b) for(int i=1;i<=(b);i++)

#define f2(i,a,b) for(int i=(a);i<=(b);i++)

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

#define rep(i,a,b,c) for(int i=(a);i!=(b);i+=(c))

#define         arrsize(a)      (sizeof(a)/sizeof(a[0]))

//#define       arrsize(a)      (sizeof(a)/sizeof(*a))

#define 	S(a)            scanf("%lld",&a)

#define 	SS(a,b)         scanf("%lld %lld",&a,&b)

#define 	SSS(a,b,c)      scanf("%lld %lld %lld",&a,&b,&c)

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

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

#define		pi              acos(-1.0)

#define	       ff               first

#define	       sc              second

typedef        pair <int, int>   pii;

typedef       pair <ll, ll>      pll;

typedef      vector< pair <ll, ll> >      vpll;

typedef		vector<ll>      vll;

typedef		map<string,ll>      msl;

typedef		map<ll,ll>      mll;

#define yes cout << "YES\n"

#define no cout<<"NO\n"

//memset(ar,-1,sizeof(ar));

//#define sort(x) sort(x.begin(), x.end())

//sort(a,a+n,greater<ll>())

//for (auto it = mp.begin(); it != mp.end(); ++it){}

// string x(w.size(),'1');

#define MAX 1000005

#define precision(a) fixed << setprecision(a)



#define mod 1000000007



 ll ar[MAX],br[MAX],cr[MAX],ar1[MAX],br1[MAX],cr1[MAX];



int main()

{

 //O_O ;

   ll n;

   cin>>n;

   for(ll i=1;i<=n;i++) cin>>ar[i],cin>>br[i],cin>>cr[i];

     ar1[n]=ar[n],br1[n]=br[n],cr1[n]=cr[n];

     for(ll i=n-1;i>=1;i--)

     {

        // cout<<"ar[i]"<<ar[i]<<nn;

         // cout<<"br1[i+1]"<<br1[i+1]<<nn;

         // cout<<"cr1[i+1]"<<cr1[i+1]<<nn;

         ar1[i]=max((ar[i]+br1[i+1]),(ar[i]+cr1[i+1]));

       //  cout<<"ar1[i]"<<ar1[i]<<nn;

         br1[i]=max((br[i]+ar1[i+1]),(br[i]+cr1[i+1]));

       //  cout<<"br1[i]"<<br1[i]<<nn;

         cr1[i]=max((cr[i]+ar1[i+1]),(cr[i]+br1[i+1]));

       //  cout<<"cr1[i]"<<cr1[i]<<nn;

    }

  /*   for(ll i=n-1;i>=1;i--)

     {

         br1[i]=max((ar[i]+ar1[i+1]),(cr[i]+cr1[i+1]));

    }

  for(ll i=n-1;i>=1;i--)

     {

         cr1[i]=max((br[i]+br1[i+1]),(ar[i]+ar1[i+1]));

    }

    */

    //ll temp=

    cout<<max(ar1[1],max(br1[1],cr1[1]))<<nn;

    return 0;

}