#include <bits/stdc++.h>
using namespace std;
#define int              long long int
#define double           long double
#define print(a)         for(auto x : a) cout << x << " "; cout << endl


const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;

inline int power(int a, int b, int mod=M) {
    int x = 1;
    a %= mod;
    while (b) {
        if (b & 1) x = (x * a) % mod; 
        a = (a * a) % mod;
        b >>= 1;
    }
    return x;
}


//_ ***************************** START Below *******************************




vector<vector<int>> a;

int consistency(int n) {
    vector<vector<int>> dp0(n, vector<int>(3, 0));
    vector<vector<int>> dp1(n, vector<int>(3, 0));
    
    dp0[0] = a[0];
    dp1[0] = {-INF, -INF, -INF}; 
    
    for(int i = 1; i < n; i++) {
        dp0[i][0] = max({dp0[i-1][1], dp0[i-1][2], dp1[i-1][1], dp1[i-1][2]}) + a[i][0];
        dp0[i][1] = max({dp0[i-1][0], dp0[i-1][2], dp1[i-1][0], dp1[i-1][2]}) + a[i][1];
        dp0[i][2] = max({dp0[i-1][0], dp0[i-1][1], dp1[i-1][0], dp1[i-1][1]}) + a[i][2];
        
        dp1[i][0] = dp0[i-1][0] + a[i][0];
        dp1[i][1] = dp0[i-1][1] + a[i][1];
        dp1[i][2] = dp0[i-1][2] + a[i][2];
    }
    
    return max({dp0[n-1][0], dp0[n-1][1], dp0[n-1][2], 
                dp1[n-1][0], dp1[n-1][1], dp1[n-1][2]});
}














int practice(int n){


    return 0;
}





void solve() {
    
    int n;
    cin>> n;
    
    a.resize(n);
    for(int i=0; i<n; i++){
    	int x, y, z;
    	cin >> x >> y >> z;
    	a[i] = {x, y, z};
    }
    
    cout << consistency(n) << endl;


}





int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}