#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define all(v) begin(v), end(v)
#define pi pair<int, int>
#define vi vector<int>
using namespace std;
const int N = 1e5+3;
const ll mod = 1e9+7;
const ll mul = 5e8 + 4;
int n, h[N], w[N];
ll cnt(ll x){
return ((x * (x+1)) % mod * mul) % mod;
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n;
for(int i = 1; i <= n; i++) cin >> h[i];
for(int i = 1; i <= n; i++) cin >> w[i];
if(is_sorted(h+1, h+n+1)){
ll res = 0;
for(int i = n; i >= 1; i--) w[i] = (w[i] + w[i+1]) % mod;
for(int i = 1; i <= n; i++){
res = (res + cnt(w[i]) * (cnt(h[i]) - cnt(h[i-1]) + mod) % mod) % mod;
}
cout << res;
}
return 0;
}
