#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
using ll = long long;
using P = pair<ll, ll>;

inline void chmax(ll& a, ll b) { if (a < b) a = b; }

int main() {
    int n;
    cin >> n;
    
    vector a(n, vector<ll>(3));
    rep(i, n)rep(j, 3) cin >> a[i][j];
    
    vector dp(n, vector<P>(3));
    rep(j, 3) {
        dp[0][j].first = a[0][j];
        dp[0][j].second = max(0ll, a[0][j]-1);
    }
    for (int i = 1; i < n; ++i) {
        rep(j, 3)rep(k, 3) if (j != k) {
            ll now = dp[i-1][k].first + dp[i-1][k].second + a[i][j];
            if (now > dp[i][j].first) {
                dp[i][j].first = now;
                dp[i][j].second = max(0ll, now-dp[i-1][k].first-1);
            }
        }
    }
    
    ll ans = 0;
    rep(j, 3) chmax(ans, dp[n-1][j].first);
    
    cout << ans << '\n';
    
	return 0;
}