#include <iostream>
#include <numeric>
using namespace std;
int main()
{
int n;
int a[1050] = {}, b[1050] = {};
cin >> n;
for (int i = 0; i < n; i++)
cin >> a[i];
for (int i = 0; i < n; i++)
cin >> b[i];
cout << inner_product(a, a + n, b, 0);
return 0;
}
int ans1()
{
int n;
int a[1050] = {};
cin >> n;
for (int i = 0; i < n; i++)
cin >> a[i];
int sum = 0, b;
for (int i = 0; i < n; i++)
{
cin >> b;
sum += b * a[i];
}
cout << sum;
return 0;
}