#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i=0; i<n; i++)
#define debug 0
#define YES cout << "Yes" << endl;
#define NO cout << "No" << endl;
using ll = long long;
using ld = long double;
const int mod = 998244353;
const int MOD = 1000000007;
const double pi = atan2(0, -1);
const int inf = 1 << 31-1;
const ll INF = 1LL << 63 - 1;
#include <time.h>
#include <chrono>

//vectorの中身を空白区切りで出力
template<typename T>
void printv(vector<T> v) {
	for (int i = 0; i < v.size(); i++) {
		cout << v[i];
		if (i < v.size() - 1) {
			cout << " ";
		}
	}
	cout << endl;
}

//vectorの中身を改行区切りで出力
template<typename T>
void print1(vector<T> v) {
	for (auto x : v) {
		cout << x << endl;
	}
}

//二次元配列を出力
template<typename T>
void printvv(vector<vector<T>> vv) {
	for (vector<T> v : vv) {
		printv(v);
	}
}

//vectorを降順にソート
template<typename T>
void rsort(vector<T>& v) {
	sort(v.begin(), v.end());
	reverse(v.begin(), v.end());
}

//昇順priority_queueを召喚
template<typename T>
struct rpriority_queue {
	priority_queue<T, vector<T>, greater<T>> pq;

	void push(T x) {
		pq.push(x);
	}

	void pop() {
		pq.pop();
	}

	T top() {
		return pq.top();
	}

	size_t size() {
		return pq.size();
	}

	bool empty() {
		return pq.empty();
	}
};

//mod mod下で逆元を算出する
//高速a^n計算(mod ver.)
ll power(ll a, ll n) {
	if (n == 0) {
		return 1;
	}
	else if (n % 2 == 0) {
		ll x = power(a, n / 2);
		x *= x;
		x %= mod;
		return x;
	}
	else {
		ll x = power(a, n - 1);
		x *= a;
		x %= mod;
		return x;
	}
}
//フェルマーの小定理を利用
ll modinv(ll p) {
	return power(p, mod - 2) % mod;
}

//Mexを求める
struct Mex {
	map<int, int> mp;
	set<int> s;
	Mex(int Max) {
		for (int i = 0; i <= Max; i++) {
			s.insert(i);
		}
	}

	int _mex = 0;
	void Input(int x) {
		mp[x]++;
		s.erase(x);
		if (_mex == x) {
			_mex = *begin(s);
		}
	}

	void Remove(int x) {
		if (mp[x] == 0) {
			cout << "Mex ERROR!: NO VALUE WILL BE REMOVED" << endl;
		}
		mp[x]--;
		if (mp[x] == 0) {
			s.insert(x);
			if (*begin(s) == x) {
				_mex = x;
			}
		}
	}

	int mex(){
		return _mex;
	}
};

int main() {
	int N;
	cin >> N;
	vector<vector<ll>> value(N, vector<ll>(3));
	rep(l, 3) {
		rep(i, N) {
			cin >> value[i][l];
		}
	}

	vector<vector<ll>> dp(N + 1, vector<ll>(6, -1));
	//level0:最初の生 1:片面焼き1 2:両面焼き 3:片面焼き後の最初 4:2度目の片面焼き 5:最後の生

	dp[0] = { 0,0,0,0,0,0 };

	rep(i, N) {
		dp[i + 1][0] = dp[i][0] + value[i][0];
		dp[i + 1][1] = max(dp[i][0], dp[i][1]) + value[i][1];
		dp[i + 1][2] = max(dp[i][0], max(dp[i][1], dp[i][2])) + value[i][2];
		dp[i + 1][3] = max(dp[i][1], dp[i][3]) + value[i][0];
		dp[i + 1][4] = max(dp[i][2],max(dp[i][3], dp[i][4])) + value[i][1];
		dp[i + 1][5] = max(dp[i][2], max(dp[i][4], dp[i][5])) + value[i][0];
	}

	ll ans = 0;
	rep(l, 6) {
		ans = max(ans, dp[N][l]);
	}
	cout << ans << endl;
}