#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll n;
ll m = 1000000007;
cin >> n;
ll h[n+5],w[n+5];
ll prefw[n+5];
ll w2 = 0;
for (int i=0;i<n;i++){
ll temp;
cin >> temp;
h[i] = temp;
}
for (int i=0;i<n;i++){
ll temp;
cin >> temp;
w[i] = temp;
w2 += temp;
w2%=m;
prefw[i] = w2;
}
stack<pair<ll,ll>> s;
ll total=0;
for (int i=0;i<n;i++){
ll num=0;
ll carry=0;
while (!s.empty() && h[s.top().first]>h[i]){
s.pop();
}
if (!s.empty()){
carry += s.top().second;
carry%=m;
//cout << carry << " ";
ll height = h[i]-h[s.top().first];
ll width = prefw[i]-prefw[s.top().first]-w[i];
height = height*(height+1)/2;
height%=m;
carry += (height*width)%m;
carry%=m;
}
else{
ll height = h[i];
ll width = prefw[i]-w[i];
height = height*(height+1)/2;
height%=m;
carry += (height*width)%m;
carry%=m;
}
//cout << carry << " ";
ll height = h[i];
ll width = w[i];
num += (carry*width)%m;
num%=m;
height = height*(height+1)/2;
ll w2 = width*(width+1)/2;
height%=m;
w2%=m;
num += (height*w2)%m;
num%=m;
carry += (height*width)%m;
carry%=m;
s.push({i,carry});
total += num;
total %=m;
}
cout << total%m;
}
