#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1LL << 60;

int main() {
    ll n; cin >> n;
    vector<ll> a(n), b(n), c(n);
    for (size_t i=0; i<n; i++) cin >> a[i];
    for (size_t i=0; i<n; i++) cin >> b[i];
    for (size_t i=0; i<n; i++) cin >> c[i];
    vector<ll> dp(9, -INF);
    dp[0] = 0;
    for (size_t i=0; i<n; i++) {
        vector<ll> dpn(9, -INF);
        for (size_t j=0; j<9; j++) {
            if (dp[j] == -INF) continue;
            ll t1 = j / 3;
            ll t2 = j % 3;
            for (ll add1=0; add1<2; add1++) for (ll add2=0; add2<2; add2++) {
                if (t1+add1 > 2 || t2+add2 > 2) continue;
                ll t1n = t1 + add1;
                ll t2n = t2 + add2;
                ll taste;
                if (t1n == 1 && t2n == 1) taste = c[i];
                else if (t1n != 1 && t2n != 1) taste = a[i];
                else taste = b[i];
                dpn[t1n*3+t2n] = max(dpn[t1n*3+t2n], dp[j] + taste);
            }
        }
        swap(dp, dpn);
    }
    ll ans = -INF;
    for (size_t i=0; i<9; i++) ans = max(ans, dp[i]);
    cout << ans << endl;
    return 0;
}