#include<iostream>
#include<vector>
using namespace std;
double producte_escalar (int n, vector <double>& v1, vector <double>& v2){
        int prod=0;
        for (int i=0; i<n; ++i){
                for (int j=0; j<n; ++j){
                        prod=prod + (v1[i] * v2[j]);
                }
        }
        return prod;
}
int main(){
        double n;
        cin >> n;
        vector<double> v1(n);
        vector<double> v2(n);
        for(int i=0; i<n; ++i) cin >> v1[i];
        for(int j=0; j<n; ++j) cin >> v2[j];
        double prod=producte_escalar (n,v1,v2);
        {cout << prod << endl;}
}