#include <bits/stdc++.h>
using namespace std;
constexpr int mod=1e9 + 7;
int f(pair<int,long long> &a){
int combs=(1ll*a.first*(a.first+1)/2)%mod;
return (1ll*combs*a.second)%mod;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n;
cin>>n;
vector<int> h(n),w(n);
for (int i=0;i<n;i++) cin>>h[i];
for (int i=0;i<n;i++) cin>>w[i];
stack<pair<int,long long>> st; //{min,cnt}
int ans=0;
int insides=0;
for (int i=n-1;i>=0;i--){
ans=(ans*2)%mod;
long long del=0;
while (!st.empty() && st.top().first>=h[i]){
ans=(ans-f(st.top())+mod)%mod;
del+=st.top().second;
st.pop();
}
st.push({h[i],del+w[i]});
ans=(ans+f(st.top()))%mod;
int inside=((1ll*w[i]*(w[i]-1)/2)%mod * (1ll*h[i]*(h[i]+1)/2)%mod)%mod;
insides=(insides+inside)%mod;
}
cout<<(ans+insides)%mod<<"\n";
return 0;
}
