#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define all(x) x.begin(),x.end()
const int mod=1e9+7;
int cal(int left,int right,int up,int down){
int width=right-left+1;
width%=mod;
int ans=width*(width-1)/2;
ans%=mod;
int tmp=up*(up+1)-down*(down+1);
tmp/=2;
tmp%=mod;
//cout<<left<<' '<<right<<' '<<up<<' '<<down<<' '<<ans*tmp<<endl;
return ans*tmp%mod;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;cin>>n;
vector<int> a(n+1),b(n+1);
for(int i=1;i<=n;i++){
cin>>a[i];
}
for(int i=1;i<=n;i++){
cin>>b[i];
b[i]+=b[i-1];
}
int ans=0;
vector<int> v;
v.push_back(0);
for(int i=1;i<=n;i++){
while(a[i]<=a[v.back()]){
//cout<<"OK"<<endl;
int tmp=v.back();
v.pop_back();
ans+=cal(b[v.back()],b[i-1],a[tmp],max(a[i],a[v.back()]));
ans%=mod;
}
v.push_back(i);
}
while(v.size()>1){
int tmp=v.back();
v.pop_back();
ans+=cal(b[v.back()],b[n],a[tmp],a[v.back()]);
ans%=mod;
}
cout<<ans<<endl;
return 0;
}
/*
4
1 3 2 4
1 1 1 1
32
*/
