#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define pii pair<int, int>
#define pl pair<ll, ll>
#define kagamine_len ios_base::sync_with_stdio(0); cin.tie(0);
#define file_in freopen("input.txt", "r", stdin);
#define file_out freopen("output.txt", "w", stdout);
#define all(x) x.begin(), x.end()
using namespace std;
/*
g++ -std=c++20 CEOI2020_Fancy_Fence.cpp -o output/CEOI2020_Fancy_Fence.exe
./output/CEOI2020_Fancy_Fence.exe
*/
const ll mod = 1e9+7;
const ll invm = 500000004;
vector<ll> hi(1e5+69), wi(1e5+69);
ll solve(int l, int r){
if (l > r) return 0;
if (l == r){
__int128_t res = ((wi[l] * (wi[l]+1) / 2) % mod) * ((hi[l] * (hi[l]+1) / 2) % mod) % mod;
return (ll)res;
}
int mid = (l+r)/2;
__int128_t le = solve(l, mid), ri = solve(mid+1, r);
__int128_t res = 0, lenl = 0, lenr = 0, curh = 2e18;
for (int i = l; i <= r; i++) curh = min((__int128_t)hi[i], curh);
for (int i = l; i <= mid; i++) lenl = (wi[i] + lenl) % mod;
for (int i = mid+1; i <= r; i++) lenr = (wi[i] + lenr) % mod;
__int128_t uwu = curh % mod * ((curh+1) % mod) % mod * invm % mod;
res = lenl * lenr % mod * uwu % mod;
res = (le + ri + res) % mod;
return (ll)res;
}
int main(){
kagamine_len
int n; cin >> n;
for (int i = 1; i <= n; i++) cin >> hi[i];
for (int i = 1; i <= n; i++) cin >> wi[i];
ll ans = solve(1, n);
cout << ans << "\n";
return 0;
}
