#include<bits/stdc++.h>
using namespace std;
using ll = long long;
int mod = 1e9 + 7;
int add(int a, int b) {
return a + b >= mod ? a + b - mod : a + b;
}
int sub(int a, int b) {
return a >= b ? a - b : a + mod - b;
}
int mul(int a, int b) {
return 1ll * a * b % mod;
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int i2 = (mod + 1) / 2;
auto sshit = [&](int x) -> int {
return mul(mul(x, x + 1), i2);
};
int n;
cin >> n;
vector<pair<int, int>> st;
vector<int> h(n), w(n);
for (auto& i : h) cin >> i;
for (auto& i : w) cin >> i;
int sum = 0;
int ans = 0;
for (int i = 0; i < n; ++i) {
int cnt = w[i];
while (st.size() && st.back().first >= h[i]) {
cnt = add(cnt, st.back().second);
sum = sub(sum, mul(sshit(st.back().first), st.back().second));
st.pop_back();
}
st.emplace_back(h[i], cnt);
sum = add(sum, mul(sshit(h[i]), cnt));
int cur = mul(sum, w[i]);
cur = sub(cur, mul(sshit(h[i]), mul(w[i], w[i])));
cur = add(cur, mul(sshit(w[i]), sshit(h[i])));
ans = add(ans, cur);
}
cout << ans;
}
