#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ii pair<ll,ll>
#define iii tuple<ll,ll,ll>
const ll inf=1e15;
const ll maxn=1e5+5;
const ll mod=1e9+7;
ll h[maxn],w[maxn];
ll ans;
struct node{
ll s,e,m;
ii val;
node *l,*r;
node (ll _s, ll _e){
s=_s,e=_e,m=(s+e)>>1,val={0,s};
if (s!=e) l=new node(s,m),r=new node(m+1,e);
}
void upd(ll x, ll v){
if (s==e){
val.first=v;
return;
}
if (x>m) r->upd(x,v);
else l->upd(x,v);
val=min(l->val,r->val);
}
ii query(ll x, ll y){
if (x<=s && e<=y) return val;
if (x>m) return r->query(x,y);
if (y<=m) return l->query(x,y);
return min(l->query(x,y),r->query(x,y));
}
}*root;
ll tri(ll x){
x%=mod;
return (x*(x+1)/2)%mod;
}
void dnc(ll l, ll r, ll par){
if (l>r) return;
ll val,pos;
tie(val,pos)=root->query(l,r);
val-=par;
ans+=(val*par%mod+tri(val))%mod*tri(w[r]-w[l-1]);
ans%=mod;
val+=par;
dnc(l,pos-1,val);
dnc(pos+1,r,val);
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
ll n;
cin>>n;
root=new node(1,n);
for (int i=1;i<=n;i++){
cin>>h[i];
root->upd(i,h[i]);
}
for (int i=1;i<=n;i++) cin>>w[i],w[i]+=w[i-1];
dnc(1,n,0);
cout<<ans;
return 0;
}
