#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<int, int>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
const int MAXN = 100 * 1000 + 17;
const ll MOD = 1000 * 1000 * 1000 + 7;
ll w[MAXN];
ll h[MAXN];
vector<int> v;
ll ile[MAXN];
ll spref[MAXN];
ll f (ll n) {
return (n * (n + 1LL)/ 2) % MOD;
}
int main () {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n;
cin >> n;
for (int i = 1; i <= n; i ++) {
cin >> h[i];
}
for (int i = 1; i <= n; i ++) {
cin >> w[i];
}
for (int i = 1; i <= n; i ++) {
spref[i] = spref[i - 1] + w[i];
}
ll wyn = 0;
ll poprz = 0;
v.pb(0);
for (int i = 1; i <= n; i ++) {
if (h[i] < h[i - 1]) {
while (!v.empty() && h[v.back()] > h[i]) {
v.pop_back();
}
int j = v.back();
poprz = ile[j];
ll sw = spref[i - 1] - spref[j];
sw %= MOD;
poprz += f(h[i]) * sw;
poprz %= MOD;
}
wyn += (w[i] - 1LL) * poprz;
wyn %= MOD;
poprz += f(h[i]) * w[i];
poprz %= MOD;
wyn += poprz;
wyn += f(h[i]) * f(w[i] - 1);
wyn %= MOD;
v.pb(i);
ile[i] = poprz;
//cout << poprz << " " << wyn << "\n";
}
cout << wyn << "\n";
return 0;
}
