/*
`-/oo+/- ``
.oyhhhhhhyo.`od
+hhhhyyoooos. h/
+hhyso++oosy- /s
.yoooossyyo:``-y`
..----.` ``.-/+:.`
`````..-::/.
`..```.-::///`
`-.....--::::/:
`.......--::////:
`...`....---:::://:
`......``..--:::::///:`
`---.......--:::::////+/`
----------::::::/::///++:
----:---:::::///////////:`
.----::::::////////////:-`
`----::::::::::/::::::::-
`.-----:::::::::::::::-
...----:::::::::/:-`
`.---::/+osss+:`
``.:://///-.
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
using ll = long long;
using ld = long double;
using pii = pair <int, int>;
using pll = pair <ll, ll>;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
template <typename T>
T Max(T a, T b) {
if(a < b) return b;
return a;
}
template <typename T>
T Min(T a, T b) {
if(a < b) return a;
return b;
}
template <typename T>
T Abs(T a) {
if(a < 0) return -a;
return a;
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
void SetIO() {
#ifdef BLAT
freopen("input.in", "r", stdin);
freopen("output.out", "w", stdout);
#endif // BLAT
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
}
const int MOD = 1e9 + 7;
const int INVMOD = (1e9 + 8) / 2;
const int INF = 1e9;
const int N = 1e5;
const int LOG = 20;
pair <int, int> p[5 + N];
ll sp[5 + N];
int n;
class RMQ {
private:
pair <int, int> r[5 + LOG][5 + N];
int log[5 + N];
public:
void Compute_RMQ() {
log[1] = 0;
for(int i = 2; i <= n; i++) log[i] = 1 + log[i >> 1];
for(int i = 1; i <= n; i++) r[0][i] = make_pair(p[i].first, i);
for(int i = 1; i <= log[n]; i++) {
for(int j = 1; j + (1 << i) - 1 <= n; j++) {
if(r[i - 1][j].first <= r[i - 1][j + (1 << (i - 1))].first)
r[i][j] = r[i - 1][j];
else r[i][j] = r[i - 1][j + (1 << (i - 1))];
//cerr << "i = " << i << "; j = " << j << '\n';
//cerr << r[i][j].first << " " << r[i][j].second << " ";
}
//cerr << '\n';
}
}
pair <int, int> Get_Minimum(int from, int to) {
int lg = log[to - from + 1];
//cerr << "lg = " << lg << '\n';
//cerr << "r[lg][from].first = " << r[lg][from].first << '\n';
//cerr << "r[lg][to - (1 << lg) + 1].first = " << r[lg][to - (1 << lg) + 1].first << '\n';
if(r[lg][from].first <= r[lg][to - (1 << lg) + 1].first)
return r[lg][from];
return r[lg][to - (1 << lg) + 1];
}
};
RMQ rmq;
ll Solve_From_To(int from, int to, int level = 0) {
if(from > to) return 0;
//cerr << from << " " << to << " " << level << '\n';
pair <int, int> minim = rmq.Get_Minimum(from, to);
//cerr << minim.first << " " << minim.second << '\n';
ll x = (sp[to] - sp[from - 1]) % MOD;
ll y = (minim.first - level) % MOD;
// level + 1 + level + 2 + ... + level + h = level * h + h * (h + 1) / 2 = h * ((h + 1) / 2 + level);
x = ((1LL * x * (x + 1)) % MOD) * INVMOD % MOD;
y = ((1LL * (y + 1) * INVMOD) % MOD + 1LL * level) * y % MOD;
ll rect = (x * y) % MOD;
//cerr << rect << '\n';
return (rect + Solve_From_To(from, minim.second - 1, minim.first) % MOD + Solve_From_To(minim.second + 1, to, minim.first) % MOD ) % MOD;
}
int main() {
SetIO();
cin >> n;
for(int i = 1; i <= n; i++) cin >> p[i].first;
for(int i = 1; i <= n; i++) {
cin >> p[i].second;
sp[i] = sp[i - 1] + 1LL * p[i].second;
}
rmq.Compute_RMQ();
cout << Solve_From_To(1, n);
return 0;
}
