#include <bits/stdc++.h>
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "
using namespace std;
typedef long long ll;
typedef pair <ll, ll> pii;
typedef pair <long double, pii> muchie;
const ll NMAX = 100001;
const ll VMAX = 101;
const ll INF = (1LL << 60);
const ll MOD = 1000000007;
const ll BLOCK = 447;
const ll base = 117;
const ll nr_of_bits = 18;
const ll inv2 = 500000004;
pii stiva[NMAX];
ll vf;
ll scor = 0;
ll h[NMAX];
ll w[NMAX];
ll lgput(ll n, ll p){
ll rez = 1;
while(p){
if(p % 2){
rez = (1LL * rez * n) % MOD;
}
n = (1LL * n * n) % MOD;
p /= 2;
}
return rez;
}
ll gauss(ll x){
return 1LL * (1LL * x * (x + 1)) % MOD * inv2 % MOD;
}
ll cate(ll h, ll w){
return (1LL * gauss(h) * gauss(w)) % MOD;
}
ll combined(ll h, ll w1, ll w2){
return (1LL * (1LL * gauss(h) * w1) % MOD * w2) % MOD;
}
void add(ll &x, ll val){
x += val;
if(x >= MOD){
x -= MOD;
}
if(x < 0){
x += MOD;
}
}
unordered_map <int, ll> mp;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
ll n, i;
ll total = 0, scor = 0;
cin >> n;
for(i = 1; i <= n; i++) cin >> h[i];
for(i = 1; i <= n; i++) cin >> w[i];
for(i = 1; i <= n; i++){
add(total, cate(h[i], w[i]));
ll avem = w[i];
while(vf && stiva[vf].first >= h[i]){
add(total, combined(h[i], stiva[vf].second, w[i]));
add(scor, -(gauss(stiva[vf].first) * stiva[vf].second) % MOD);
add(avem, stiva[vf].second);
vf--;
}
add(total, (scor * w[i]) % MOD);
stiva[++vf] = {h[i], avem};
add(scor, (gauss(stiva[vf].first) * stiva[vf].second) % MOD);
}
cout << total;
return 0;
}
