#include<bits/stdc++.h>
using namespace std;
int main(){
cin.tie(0)->sync_with_stdio(0);
int n;
cin >> n;
vector<long long> h(n + 1);
for(int i = 1;i <= n;i ++){
cin >> h[i];
}
vector<long long> w(n + 1);
for(int i = 1;i <= n;i ++){
cin >> w[i];
}
vector<int> L(n + 1);
for(int i = 1;i <= n;i ++){
L[i] = i - 1;
while(L[i] > 0 && h[i] < h[L[i]]){
L[i] = L[L[i]];
}
}
vector<int> R(n + 1);
for(int i = n;i >= 1;i --){
R[i] = i + 1;
while(R[i] <= n && h[i] <= h[R[i]]){
R[i] = R[R[i]];
}
}
long long ans = 0;
vector<long long> sum(n + 1);
for(int i = 1;i <= n;i ++){
sum[i] = sum[i - 1] + w[i];
}
for(int i = 1;i <= n;i ++){
ans += w[i] * (w[i] + 1) * h[i] * (h[i] + 1) / 4;
ans += ((sum[i] - sum[L[i]]) * (sum[R[i] - 1] - sum[i - 1]) - 1LL * w[i] * w[i]) * h[i] * (h[i] + 1) / 2;
}
cout << ans << '\n';
}
