// Source: https://usaco.guide/general/io
#include <bits/stdc++.h>
using namespace std;
#define int int64_t
const int M = 1e9+7;
int32_t main() {
int n; cin >> n;
vector<int> w , h;
w.push_back(0);
h.push_back(0);
for(int i = 0; i < n; i++){
int x; cin >> x;
h.push_back(x);
}
for(int i = 0; i < n; i++){
int x; cin >> x;
w.push_back(x+w.back());
}
w.push_back(w.back());
h.push_back(0);
vector<int> l(n+2 ,-1) , r(n+2 ,-1);
stack<int> s1 , s2;
s1.push(0);
for(int i = 1; i <= n; i++){
while(h[s1.top()] > h[i]){
s1.pop();
}
l[i]=s1.top();
s1.push(i);
}
s2.push(n+1);
for(int i = n; i >= 1; i--){
while(h[s2.top()] >= h[i]){
s2.pop();
}
r[i]=s2.top();
s2.push(i);
}
int ans = 0;
for(int i = 1; i <= n; i++){
//cout << i << " " << l[i] << " " << r[i] << endl;
int u = max(h[l[i]] , h[r[i]]);
int v = w[r[i]-1]-w[l[i]];
ans+=((v*(v+1)/2)%M)*(((h[i])*(h[i]+1)/2-(u)*(u+1)/2)%M);
//cout << v << " " << u << " " << h[i] << endl;
//cout << ans << endl;
ans%=M;
}
cout << ans << endl;
}
