#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
using namespace std;
const int N = 2e5 + 5;
const ll mod = 1e9 + 7;
ll Add(ll a, ll b) {
a += b;
if (a >= mod) a -= mod;
return a;
}
ll Sub(ll a, ll b) {
a -= b;
if (a < 0) a += mod;
return a;
}
ll Md(ll x) {
while (x < 0) x += mod;
while (x >= mod) x -= mod;
return x;
}
ll Mul(ll a, ll b) {
return (a * b) % mod;
}
ll Exp(ll x, ll k) {
ll ans = 1;
for (; k; k >>= 1) {
x = Mul(x, x);
if (k & 1) ans = Mul(ans, x);
}
return ans;
}
ll Div(ll a, ll b) {
return Mul(a, Exp(b, mod - 2));
}
ll G(ll x) {
ll y = x * (x + 1) / 2;
y %= mod;
return y;
}
ll F(ll H, ll W) {
H = G(H);
W = G(W);
H %= mod;
W %= mod;
return Mul(H, W);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n;
cin >> n;
vector<ll> h(n), w(n), p(n);
for (int i = 0; i < n; i++) {
cin >> h[i];
}
for (int i = 0; i < n; i++) {
cin >> w[i];
p[i] = w[i];
if (i > 0) p[i] = Add(p[i], p[i - 1]);
}
ll ans = 0;
stack<int> s;
for (int i = 0; i < n; i++) {
while (!s.empty() && h[s.top()] > h[i]) {
int j = s.top();
s.pop();
int k = -1;
if (!s.empty()) k = s.top();
ll mx = h[i];
if (k != -1) mx = max(mx, h[k]);
ll H = h[j] - mx;
ll W = p[i - 1];
if (k != -1) W = Sub(W, p[k]);
ans = Add(ans, F(H, W));
ans = Add(ans, Mul(G(W), Mul(H, mx)));
}
s.push(i);
}
while (!s.empty()) {
int j = s.top();
s.pop();
int k = -1;
if (!s.empty()) k = s.top();
ll mx = 0;
if (k != -1) mx = max(mx, h[k]);
ll H = h[j] - mx;
ll W = p[n - 1];
if (k != -1) W = Sub(W, p[k]);
ans = Add(ans, F(H, W));
ans = Add(ans, Mul(G(W), Mul(H, mx)));
}
cout << ans << en;
return 0;
}
