#include <bits/stdc++.h>
#define ll long long
#define fr first
#define sc second
#define ps push
#define pp pop
#define psb push_back
#define ppb pop_back
#define ft front
using namespace std;
const ll mod = 1e9 + 7;
ll expo(ll a, ll b){
if(b == 1) return a;
else if(b == 0) return 1;
else{
ll x = expo(a, b / 2); x *= x; x %= mod;
if(b & 1) return (x * a) % mod;
else return x;
}
}
ll seq(ll a){
return (((a * (a + 1)) % mod) * expo(2, mod - 2)) % mod;
}
ll comb_grid(ll a, ll b){
return (a * b) % mod;
}
int main(){
int n; cin >> n;
ll h[n], new_h[n] = {0};
priority_queue <pair <ll, int>> pq;
for(int i = 0; i < n; i++){
cin >> h[i];
pq.ps({h[i], i});
new_h[i] = LLONG_MAX;
}
ll w[n], new_w[n];
for(int i = 0; i < n; i++){
cin >> w[i];
new_w[i] = 0;
}
ll ans = 0;
int point_l[n]; memset(point_l, -1, sizeof(point_l));
int point_r[n]; memset(point_r, -1, sizeof(point_r));
bool done[n] = {0};
while(!pq.empty()){
auto [h_now, i] = pq.top(); pq.pop();
if(!done[i]){
//find l & r
int l = i, r = i;
done[i] = 1;
ll tot = w[i];
while(0 <= l - 1 && h[l - 1] == h[i]){
l--;
tot += w[l], tot %= mod;
done[l] = 1;
}
while(r + 1 < n && h[r + 1] == h[i]){
r++;
tot += w[r], tot %= mod;
done[r] = 1;
}
//update pointer
int new_l = l, new_r = r;
while(0 <= new_l - 1 && point_l[new_l - 1] != -1) new_l = point_l[new_l - 1];
while(new_r + 1 < n && point_r[new_r + 1] != -1) new_r = point_r[new_r + 1];
point_r[new_l] = new_r;
point_l[new_r] = new_l;
ll h_min = min({h_now, h[new_r], h[new_l]});
//ans
ans += comb_grid(seq(h[i]), seq(tot)), ans %= mod;
// cout << h[i] << ' ' << tot << ": " << comb_grid(seq(h[i]), seq(tot)) << '\n';
if(r + 1 < n && done[r + 1]) ans += comb_grid((h_min * new_w[new_r]) % mod, (h_min * tot) % mod), ans %= mod;
if(0 <= l - 1 && done[l - 1]) ans += comb_grid((h_min * new_w[new_l]) % mod, (h_min * tot) % mod), ans %= mod;
if((0 <= l - 1 && done[l - 1]) && (r + 1 < n && done[r + 1])) ans += comb_grid((h_min * new_w[new_l]) % mod, (h_min * new_w[new_r]) % mod), ans %= mod;
//update new_w
ll w_new_l = new_w[new_l], w_new_r = new_w[new_r];
new_w[new_l] += tot + w_new_r, new_w[new_l] %= mod;
new_w[new_r] = new_w[new_l];
//update new_h
new_h[new_l] = h_min;
new_h[new_r] = h_min;
}
}
cout << ans;
}
