#include <bits/stdc++.h>
using namespace std;

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int N;
    cin >> N;

    vector<int> a(N + 1), b(N + 1), c(N + 1);
    vector<int64_t> pre(N + 1);
    for (int i = 1; i <= N; i++) {
        cin >> a[i];
    }
    for (int i = 1; i <= N; i++) {
        cin >> b[i];
    }
    for (int i = 1; i <= N; i++) {
        cin >> c[i];
    }

    for (int i = 1; i <= N; i++) {
        pre[i] = pre[i - 1] + a[i];
    }

    vector<int> dp(N + 1);

    const auto ok = [&](int64_t L) {
        fill(dp.begin(), dp.end(), false);
        int64_t mx = -pre[0] + b[1];
        for (int i = 1; i <= N; i++) {
            if (pre[i] + c[i] + mx >= L) {
                dp[i] = true;
                if (i < N)
                    mx = max(mx, -pre[i] + b[i + 1]);
            }
        }
        return dp[N];
    };

    int64_t ans = 0;
    for (int64_t s = 1LL << 60; s; s >>= 1) {
        if (ok(ans + s)) {
            ans += s;
        }
    }

    cout << ans << '\n';
    return 0;
}