#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define fix(x) fixed << setprecision(x)
#define asc(x) x, vector<x>, greater<x>
#define rep(i, n) for(ll i = 0; i < n; ++i)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<ll> a(n), b(n), c(n);
    rep(i,n) cin >> a[i];
    rep(i,n) cin >> b[i];
    rep(i,n) cin >> c[i];
    vector<ll> dp1(5,0), dp2(5,0);
    rep(i,n){
        vector<ll> upd(5,0);
        rep(j,4) chmax(upd[j+1], dp1[j]);
        rep(j,4) chmax(upd[j], dp1[j]);
        upd[0] += a[i];
        upd[1] += b[i];
        upd[2] += c[i];
        upd[3] += b[i];
        upd[4] += a[i];
        dp1 = upd;
        upd = vector<ll>(5,0);
        rep(j,4) chmax(upd[j+1], dp2[j]);
        rep(j,4) chmax(upd[j], dp2[j]);
        upd[0] += a[i];
        upd[1] += b[i];
        upd[2] += a[i];
        upd[3] += b[i];
        upd[4] += a[i];
        dp2 = upd;
    }
    cout << max(*max_element(all(dp1)), *max_element(all(dp2))) << '\n';
    return 0;
}