#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;}
}