#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
const int N = 1e6 + 10;

int n;
#define int long long

const ll Eps = 1e17, L = 1, R = 1e18;

struct Tree {
#define LOG 65
    int root, cnt;
    ll Mi, Ma;
    vector<int> ls, rs;
    vector<ll> MAX1, MAX2;

    Tree(int M = 0, ll Min = 1, ll Max = 2e18) : ls(M * LOG), rs(M * LOG), MAX1(M * LOG), MAX2(M * LOG) {
        root = 0, cnt = 0;
        Mi = Min, Ma = Max;
    }

    inline void pushup(int p) {
        MAX1[p] = max(MAX1[ls[p]], MAX1[rs[p]]);
        MAX2[p] = max(MAX2[ls[p]], MAX2[rs[p]]);
    }

    inline void New(int &p) {
        p = ++cnt;
        MAX1[p] = MAX2[p] = -Eps;
    }

    inline void update(int &p, ll l, ll r, ll x, ll w1, ll w2) {
        if (!p) New(p);
        if (l == r) {
            MAX1[p] = max(MAX1[p], w1);
            MAX2[p] = max(MAX2[p], w2);
            return;
        }
        int mid = l + r >> 1;
        if (x <= mid) update(ls[p], l, mid, x, w1, w2);
        else update(rs[p], mid + 1, r, x, w1, w2);
        pushup(p);
    }

    inline void update(int x, ll w1, ll w2) { update(root, Mi, Ma, x, w1, w2); }

    inline ll query1(int p, ll l, ll r, ll x, ll y) {
        if (!p) return -Eps;
        if (x <= l && r <= y) return MAX1[p];
        ll ans = -Eps;
        int mid = l + r >> 1;
        if (x <= mid) ans = max(ans, query1(ls[p], l, mid, x, y));
        if (y > mid) ans = max(ans, query1(rs[p], mid + 1, r, x, y));
        return ans;
    }

    inline ll query1(ll l, ll r) { return query1(root, Mi, Ma, l, r); }

    inline ll query2(int p, ll l, ll r, ll x, ll y) {
        if (!p) return -Eps;
        if (x <= l && r <= y) return MAX2[p];
        ll ans = -Eps;
        int mid = l + r >> 1;
        if (x <= mid) ans = max(ans, query2(ls[p], l, mid, x, y));
        if (y > mid) ans = max(ans, query2(rs[p], mid + 1, r, x, y));
        return ans;
    }

    inline ll query2(ll l, ll r) { return query2(root, Mi, Ma, l, r); }
};


void solve() {
    cin >> n;
    vector<ll> a(n + 5), b(n + 5), c(n + 5), sum(n + 5);
    vector<ll> dp(n + 5, -Eps);
    Tree T(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) cin >> b[i];
    for (int i = 0; i < n; i++) cin >> c[i];
    sum[0] = a[0];
    for (int i = 1; i < n; i++) sum[i] = a[i] + sum[i - 1];

    for (int i = 0; i < n; i++) {
        if (i == 0) {
            dp[i] = a[i] + b[i] + c[i];
        } else {
            for (int j = 0; j < i; j++) {
                dp[i] = max(dp[i], min(dp[j], b[j + 1] + c[i] + sum[i] - sum[j]));
            }
            dp[i] = max(dp[i], b[0] + c[i] + sum[i]);
        }
//            T.update(dp[i] - b[i + 1] + sum[i] + Eps, dp[i], b[i + 1] - sum[i]);
//        } else {
//            ll x = c[i] + sum[i] + Eps;
//            dp[i] = max(T.query1(L, x), T.query2(x, R) + c[i] + sum[i]);
//            if (i != n - 1)T.update(dp[i] - b[i + 1] + sum[i] + Eps, dp[i], b[i + 1] - sum[i]);
//        }
    }
    cout << dp[n - 1] << '\n';

}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int _ = 1;
//    cin >> _;
    for (int o = 1; o <= _; o++) {
        //      cout << "Case #<<" << o << ": ";
        solve();
    }
    return 0;
}

/*


11
-323225375 -897098227 -795978453 501188072 409939326 -362890219 969123048 962633819 252457646 694824070 -406990840
-696821643 -663750226 -570551722 670541392 172964990 399404695 -305728788 -157617655 -801518744 -328729631 -160335217
-465411342 -660775657 515997870 -34787742 628368976 84800619 -728713779 573207953 115652694 -686953578 -215986240

91174984

*/