#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O1")
#define ll long long
#define pii pair<ll,ll>
#define pi pair<ll,pii>
#define fi first
#define se second
const ll N=2e5+1005,MOD=1e9+7,INF=1e18;
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
int t=1;//cin>>t;
while(t--){
ll n;cin>>n;
ll h[n+5],w[n+5];
h[0]=h[n+1]=0;
vector<pii> v;
vector<ll> pref(n+5, 0);
for(int i=1; i<=n; i++)cin>>h[i],v.push_back({h[i],i});
for(int i=1; i<=n; i++){
cin>>w[i];
pref[i]=pref[i-1]+w[i];
}
sort(v.begin(),v.end());
set<ll> s;
s.insert(0);
s.insert(n+1);
ll ans=0;
for(pii i : v){
auto it=s.upper_bound(i.se);
ll r=*it;
ll l=*(--it);
//cout<<l<<" "<<r<<"\n";
s.insert(i.se);
ll len=pref[r-1]-pref[l],bef=max(h[r],h[l]);
ll ad=(((h[i.se]*(h[i.se]+1))/2)%MOD*((len*(len+1))/2)%MOD)%MOD;
ll neg=(((bef*(bef+1))/2)%MOD*((len*(len+1))/2)%MOD)%MOD;
ad=((ad-neg)%MOD+MOD)%MOD;
ans=(ad+ans)%MOD;
}
cout<<ans;
}
}
