#include <bits/stdc++.h>
using namespace std;
#define int long long
const int mod = 1e9 + 7;
int s(int x) {
return (x * (x + 1) / 2) % mod;
}
int s(int l, int r) {
return (s(r) - s(l-1)) % mod;
}
void norm(int& x) {
x = (x % mod + mod) % mod;
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
int n;
cin >> n;
stack<pair<int, int>> st;
int sum = 0, delta = 0;
vector<int> H(n+1), W(n+1);
for (int i = 1; i <= n; i++) cin >> H[i];
for (int i = 1; i <= n; i++) cin >> W[i];
for (int i = 1; i <= n; i++) {
int h = H[i], w = W[i], aw = w;
while (!st.empty() && st.top().first >= h) {
auto [ff, ss] = st.top();
st.pop();
int nxth = h;
if (!st.empty() && st.top().first >= h) nxth = st.top().first, st.top().second += ss;
else aw += ss;
delta -= (s(nxth + 1, ff) * ss) % mod;
norm(delta);
}
// cout << delta << ' ' << h << ' ' << w << '\n';
st.push({h, aw});
sum += delta * w + s(h) * s(w);
norm(sum);
delta += s(h) * w;
norm(delta);
// cout << sum << ' ' << delta << '\n';
}
cout << sum << '\n';
}
