#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
const ll LOG = 31;
const ll MOD = 1000000007;
const ll inf = 1e17;
const ll inv = (MOD + 1) / 2;
#define db(x) cerr << #x << " = " << x << " | "
#define dbg(x) cerr << #x << " = " << x << "\n"
#define Algerian ios::sync_with_stdio(0);
#define OI cin.tie(NULL);
ll nc2(ll n) { return ((((n % MOD) * ((n - 1) % MOD)) % MOD)* inv) % MOD; }
void add(ll& a, ll b) {
a = (a + b) % MOD;
}
void sub(ll& a, ll b) {
a = (a - b + MOD) % MOD;
}
int main() {
Algerian OI
ll n;
cin >> n;
map<ll, vector<ll>> heights;
vector<ll> h(n), w(n), p(n);
ll r = 0;
for (ll i = 0; i < n; i++) cin >> h[i];
for (ll i = 0; i < n; i++) { cin >> w[i]; r += w[i], p[i] = r;}
for (ll i = 0; i < n; i++) {
heights[h[i]].push_back(i);
}
set<ll> points = {-1, n};
// multiset<ll> len = {p[n - 1]};
ll cur_segments = nc2(p[n - 1]);
ll res = 0;
for (ll i = 0; i < n; i++) res += (h[i] + nc2(h[i])) * w[i];
// dbg(res);
ll pre = 0;
for (auto& [u, v] : heights) {
// dbg(u);
ll delta = u - pre;
add(res, cur_segments * (nc2(delta) + delta + delta * pre));
pre = u;
for (auto& pt : v) {
auto it = points.lower_bound(pt);
ll r = *it, l = *prev(it);
ll length = p[r - 1] - (l >= 0 ? p[l] : 0);
// len.erase(len.find(length));
// dbg("here");
sub(cur_segments, nc2(length));
points.insert(pt);
ll new_len[] = {(pt > 0 ? p[pt - 1] : 0) - (l >= 0 ? p[l] : 0), p[r - 1] - p[pt]};
// len.insert(new_len[0]);
// len.insert(new_len[1]);
add(cur_segments, nc2(new_len[0]));
add(cur_segments, nc2(new_len[1]));
}
}
cout << res << "\n";
return 0;
}
