#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
using std::mt19937_64;
using std::random_device;
using std::uniform_int_distribution;
#include <numeric>
#define ff first
#define ss second
#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define vi vector<int>
#define mii map<int,int>
#define pqb priority_queue<int>
#define pqs priority_queue<int,vi,greater<int> >
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007
#define inf 1e18
#define ps(x,y) fixed<<setprecision(y)<<x
#define mk(arr,n,type) type *arr=new type[n];
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
void c_p_c()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifndef ONLINE_JUDGE
freopen("art2.in", "r", stdin);
freopen("art2.out", "w", stdout);
#endif
}
int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, 1, -1};
int exp(int x, int n, int m) {
if(x == 0 and n == 0) return 1;
x %= m;
int res = 1;
while (n > 0) {
if (n % 2 == 1) { res = res * x % m; }
x = x * x % m;
n /= 2;
}
return res;
}
int modinv(int n) {
int r = 1;
int p = mod - 2;
while (p > 0) {
if (p % 2 == 1) {
r = (r * n) % mod;
}
n = (n * n) % mod;
p /= 2;
}
return r;
}
int mul(int a,int b){
return ((a*b)%mod);
}
int val(int a){
return ((((a*(a+1))%mod)*modinv(2))%mod);
}
signed main()
{
int t=1;
// c_p_c();
// cin >> t;
while(t--){
int n;
cin >> n;
vector<int> h(n+1),w(n+1);
for(int i = 1 ; i <= n; i++) cin >> h[i];
for(int i = 1 ; i <= n; i++) cin >> w[i];
stack<pair<int,int>> s;
int ans = 0;
for(int i = 1 ; i <= n; i++){
if(s.empty() or s.top().ff <= h[i]){
if(!s.empty() and s.top().ff == h[i]){
s.top().ss = (w[i]+s.top().ss)%mod;
}
else{
s.push({h[i],w[i]});
}
}
else{
int width = 0;
while(!s.empty() and s.top().ff > h[i]){
ans = (ans + mul(val(s.top().ff),val(width+s.top().ss)))%mod;
ans = (ans - mul(val(s.top().ff),val(width))+mod)%mod;
width = (width+s.top().ss)%mod;
s.pop();
}
ans = (ans - mul(val(h[i]),val(width)+mod))%mod;
if(!s.empty() and s.top().ff == h[i]){
s.top().ss = (s.top().ss+(w[i]+width))%mod;
}
else{
s.push({h[i],(w[i]+width)%mod});
}
}
// cout<<ans<<endl;
}
int width = 0;
while(!s.empty()){
ans = (ans + mul(val(s.top().ff),val(width+s.top().ss)))%mod;
ans = (ans - mul(val(s.top().ff),val(width))+mod)%mod;
width = (width+s.top().ss)%mod;
s.pop();
}
cout<<ans<<endl;
}
return 0;
}
