#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define ff first
#define ss second
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()
const ll mod=1e9+7;
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
ll n;
cin>>n;
ll h[n+5],w[n+5];
for(ll i=1;i<=n;i++){
cin>>h[i];
}
for(ll i=1;i<=n;i++){
cin>>w[i];
}
ll ans=0;
for(ll i=1;i<=n;i++){
ans+=(w[i]*(w[i]+1)/2%mod)*(h[i]*(h[i]+1)/2%mod)%mod;
if(ans>=mod) ans-=mod;
ll mn=h[i];
for(ll j=i+1;j<=n;j++){
mn=min(mn,h[j]);
ans+=(w[i]*w[j]%mod)*(mn*(mn+1)/2%mod)%mod;
if(ans>=mod) ans-=mod;
}
}
cout<<ans;
}
