#include<bits/stdc++.h>
#pragma GCC target("avx2")
#define rep(i, a, b) for (ll i = (a); i < (b); i++)
#define all(x) (x).begin(), (x).end()
#define sz(x) (ll)size(x)
using namespace std;
using ll = long long;
using vi = vector<ll>;
using vvi = vector<vi>;
using pii = pair<ll, ll>;

#define TIME chrono::steady_clock::now().time_since_epoch().count()
mt19937 rng(TIME);

const double sec = 1.9;
auto start = TIME;

using S = array<int,4>;
using P = int;


constexpr int L = 2e6;
int n;
vector<int> f, t, dir;
#define truemod(a) (((a) % L + L) % L)
P eval(S x) {
    int time = 0, loc = 0;
    rep(i,0,n) {
        int best_wait = 1e9;
        for (int q : x)
            best_wait = min(best_wait, truemod((loc + q - time) * (dir[i] ?: -1)));
        time += best_wait + t[i];
        loc = f[i];
    }
    return time;
}

S mut(S x) {
    int ch = rng() % 3, gah = rng() % 2 * 2 - 1;
    x[ch] = truemod(x[ch] + (1 << (rng() % 20)) * gah);
    return x;
}

pair<S, P> SA(S current, P price) {
    double p, t_start = 10, t_end = 1e-3;
    P obj = price; S best = current;
    auto accept = [&] (P new_price) {
        double t = t_start * pow(t_end / t_start, p);
        return bernoulli_distribution(
            min(1.0, exp((price - new_price) / t))
            )(rng);
    };
    while ((p = (TIME - start) / sec / 1e9) < 1) {
        S x = mut(current);
        P np = eval(x);
        if (accept(np)) current = x, price = np;
        if (price < obj) best = current, obj = price;
    }
    return {best, obj};
}

void solve() {
    cin >> n;
    f.resize(n), t.resize(n);
    dir.resize(n);
    for (auto& x : f)
        cin >> x;

    ll ans = 0;
    for (auto& x : t) {
        cin >> x;
        ans += x / L * L;
        x %= L;
    }
    ll last = 0;
    rep(i,0,n) dir[i] = f[i] > last, t[i] += abs(last - f[i]), last = f[i];

    S init{0, 0, 0, 0};
    auto [best, obj] = SA(init, eval(init));
    for (auto x : best) cerr << x << ' ';
    cout << ans + obj;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    solve();

    return 0;
}