#include <bits/stdc++.h>

using namespace std;

int main() {
    int a[1000], b[1000], n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    for (int i = 0; i < n; i++) {
        cin >> b[i];
    }
    int ab = 0;
    for (int i = 0; i < n; ++i) {
        ab += a[i] * b[i];
    }
    cout << ab << endl;
    return 0;
}