#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define endl '\n'
const ll mod = 1e9 + 7;
const int N = 1e5 + 5;
const ll inv2 = 500000004;
int n;
ll h[N], w[N];
ll pre[N];
stack<int> s;
int l[N], r[N];
ll S(ll n) {
n %= mod;
ll res = n;
res = (res * (n + 1)) % mod;
res = (res * inv2) % mod;
return res;
}
void solve() {
pre[0] = 0;
for (int i = 1; i <= n; ++i) {
pre[i] = (pre[i - 1] + w[i]);
}
for (int i = 1; i <= n; ++i) {
while (!s.empty() && h[s.top()] >= h[i]) s.pop();
l[i] = (s.empty() ? 0 : s.top());
s.push(i);
}
while (!s.empty()) s.pop();
for (int i = n; i >= 1; --i) {
while (!s.empty() && h[s.top()] >= h[i]) s.pop();
r[i] = (s.empty() ? n + 1 : s.top());
s.push(i);
}
ll ans = 0;
for (int i = 1; i <= n; ++i) {
ll W = (pre[r[i] - 1] - pre[l[i]]);
ll prev_h = 0;
if (l[i] > 0) prev_h = max(prev_h, h[l[i]]);
if (r[i] <= n) prev_h = max(prev_h, h[r[i]]);
ll count_W = S(W);
ll count_H_total = S(h[i]);
ll count_H_prev = S(prev_h);
ll count_H_new = (count_H_total - count_H_prev + mod) % mod;
ll contribution = (count_W * count_H_new) % mod;
ans = (ans + contribution) % mod;
}
cout << ans << endl;
}
void input() {
cin >> n;
for (int i = 1; i <= n; ++i) cin >> h[i];
for (int i = 1; i <= n; ++i) cin >> w[i];
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
input();
solve();
return 0;
}
