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