#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vi vector<int>
#define vl vector<ll>
#define ov4(a, b, c, d, name, ...) name
#define rep3(i, a, b, c) for(ll i = (a); i < (b); i += (c))
#define rep2(i, a, b) rep3(i, a, b, 1)
#define rep1(i, n) rep2(i, 0, n)
#define rep0(n) rep1(aaaaa, n)
#define rep(...) ov4(__VA_ARGS__, rep3, rep2, rep1, rep0)(__VA_ARGS__)
#define per(i, a, b) for(ll i = (a) - 1; i >= (b); i--)
#define fore(e, v) for(auto &&e : v)
#define all(a) begin(a), end(a)
#define si(a) (int)(size(a))
#define lb(v, x) (lower_bound(all(v), x) - begin(v))
#define eb emplace_back

template <typename T, typename S> bool chmin(T &a, const S &b) { return a > b ? a = b, 1 : 0; }
template <typename T, typename S> bool chmax(T &a, const S &b) { return a < b ? a = b, 1 : 0; }

const int INF = 1e9 + 100;
const ll INFL = 3e18 + 100;

#define i128 __int128_t

struct _ {
    _() { cin.tie(0)->sync_with_stdio(0), cout.tie(0); }
} __;

int main() {
    int n;
    cin >> n;
    vl a(n), b(n), c(n);
    fore(e, a) cin >> e;
    fore(e, b) cin >> e;
    fore(e, c) cin >> e;

    ll ma = 0;
    // 0 (1 or 2) 0

    vector<vl> dp(n + 1, vl(3, -INFL));
    dp[0][0] = dp[0][1] = dp[0][2] = 0;
    rep(i, n) {
        chmax(dp[i + 1][0], dp[i][0] + a[i]);
        chmax(dp[i + 1][1], max(dp[i][0] + a[i], dp[i][1] + max(b[i], c[i])));
        chmax(dp[i + 1][2], max(dp[i][1] + max(b[i], c[i]), dp[i][2] + a[i]));
    }
    chmax(ma, *max_element(all(dp[n])));

    // 0 1 0 1 0
    dp = vector<vl>(n + 1, vl(5, -INFL));
    rep(j, 5) dp[0][j] = 0;
    rep(i, n) {
        chmax(dp[i + 1][0], dp[i][0] + a[i]);
        rep(j, 1, 5) {
            chmax(dp[i + 1][j], dp[i][j - 1] + (j & 1 ? a[i] : b[i]));
            chmax(dp[i + 1][j], dp[i][j] + (~j & 1 ? a[i] : b[i]));
        }
    }
    chmax(ma, *max_element(all(dp[n])));
    cout << ma << endl;
}