#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
const int M = 1e9 + 7;
void add(int &x, int y) {
if ((x += y) >= M) {
x -= M;
}
if (x < 0) {
x += M;
}
}
int C2(int x) {
return (long long) x * (x + 1) / 2 % M;
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
int n; cin >> n;
vector<int> h(n), w(n);
for (int &x : h) {
cin >> x;
}
vector<int> st;
int sum = 0, res = 0;
for (int i = 0; i < n; ++i) {
cin >> w[i];
int x = 0;
while (st.size() && h[st.back()] >= h[i]) {
add(x, w[st.back()]);
add(sum, (long long) -w[st.back()] * C2(h[st.back()]) % M);
st.pop_back();
}
add(res, (long long) w[i] * x % M * C2(h[i]) % M);
add(res, (long long) w[i] * sum % M);
add(res, (long long) C2(w[i]) * C2(h[i]) % M);
add(x, w[i]);
w[i] = x;
add(sum, (long long) w[i] * C2(h[i]) % M);
st.push_back(i);
}
cout << res;
return 0;
}
