#include <iostream>

#include <vector>

#include <algorithm>

using namespace std;

int main(){

ios_base::sync_with_stdio(0); cin.tie(0);

int n;

cin >> n;

vector<long long> v;

vector<long long> vsort;

vector<long long> length;

long long sum = 0;

for(int i=0; i<n-1; i++){

long long num;

cin >> num;

length.push_back(num);

sum += num;

}

for(int i=0; i<n-1; i++){

long long num;

cin >> num;

v.push_back(num);

vsort.push_back(num);

}

sort(vsort.begin(), vsort.end());

long long res = 0;

int cnt = 0;

for(int i=0; i<n-1; i++){

if(v[i] == vsort[0]){

res += v[i] * sum;

cout << res;

return 0;

}

else{

if(v[i] < v[cnt]){

res += v[i] * length[i];

sum -= length[i];

cnt = i;

}

else{

res += v[cnt] * length[i];

sum -= length[i];

}

}

}

}