#include <bits/stdc++.h>
#define pb push_back
#define ll long long
#define vll vector<ll>
#define vbool vector<bool>
#define pairll pair<ll,ll>
#define fi first
#define sc second
#define rever greater<ll>()
using namespace std;
ll res = 0, md = 1e9+7;
vll pw(30);
ll mn(vector<vll> &st, vll &h, ll l, ll r){
ll lg = log2(r-l+1);
if(h[st[lg][l]] < h[st[lg][r-pw[lg]+1]]){
return st[lg][l];
}else return st[lg][r-pw[lg]+1];
}
ll v(ll x){
return (x*(x+1)/2)%md;
}
void dnc(vll &h, vll &w, vector<vll> &st, ll l, ll r, ll k){
if(l > r)return;
ll mid = mn(st, h, l, r);
if(k < h[mid]){
ll wid = w[r];
if(l>0)wid -= w[l-1];
res += (v(wid)*v(h[mid]))%md;
res %= md;
res += md - ((v(wid)*v(k))%md);
res %= md;
}
if(l==r)return;
dnc(h, w, st, l, mid-1, h[mid]);
dnc(h, w, st, mid+1, r, h[mid]);
}
void solve(){
ll n; cin >> n;
vll h(n), w(n);
for(ll i = 0; i < n; i++) cin >> h[i];
for(ll i = 0; i < n; i++) cin >> w[i];
for(ll i = 1; i < n; i++) w[i]+=w[i-1];
vector<vll> st(20, vll(n));
pw[0]=1; for(ll i = 1; i < 30; i++)pw[i]=pw[i-1]*2;
for(ll i = 0; i < n; i++)st[0][i] = i;
for(ll i = 1; i < 20; i++){
for(ll j = 0; j+pw[i]-1 < n; j++){
if(h[st[i-1][j]] < h[st[i-1][j+pw[i-1]]]){
st[i][j] = st[i-1][j];
}else st[i][j] = st[i-1][j+pw[i-1]];
}
}
dnc(h, w, st, 0, n-1, 0);
cout << res << endl;
}
int main(){
ios::sync_with_stdio(false); cin.tie(nullptr);
ll t=1; //cin >> t;
for(int i = 1; i <= t; i++){
solve();
}
}
