#include<bits/stdc++.h>
using namespace std;
using ll=long long;
constexpr int mod=1e9+7;
vector<int>fnxt(vector<ll>&v){
int n=v.size();
vector<int>res(n,n);
stack<int>s;
for(int i=n-1;i>=0;--i){
while(!s.empty() and v[i]<=v[s.top()])s.pop();
if(!s.empty())res[i]=s.top();
s.push(i);
}
return res;
}
vector<int>fprev(vector<ll>&v){
int n=v.size();
vector<int>res(n,0);
stack<int>s;
for(int i=0;i<n;++i){
while(!s.empty() and v[i]<v[s.top()])s.pop();
if(!s.empty())res[i]=s.top();
s.push(i);
}
return res;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int n;
cin>>n;
vector<ll>h(n+1),w(n+1),p(n+1);
for(int i=1;i<=n;++i)cin>>h[i];
for(int i=1;i<=n;++i){
cin>>w[i];
p[i]=p[i-1]+w[i];
}
vector<int>nxt=fnxt(h),prev=fprev(h);
ll res=0;
for(int i=1;i<=n;++i){
ll ver=h[i]*(h[i]+1ll)/2%mod;
ll before=(p[i-1]-p[prev[i]])%mod;
ll after=(p[nxt[i]-1]-p[i])%mod;
res+=after*before%mod*ver%mod;
res+=w[i]*before%mod*ver%mod;
res%=mod;
res+=w[i]*after%mod*ver%mod;
res+=w[i]*(w[i]+1)/2%mod*ver%mod;
res%=mod;
}
cout<<res<<'\n';
}
