package com.study.demo;

import java.util.Scanner;

public class test3_2 {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    int n = scanner.nextInt();
    int[] a = new int[n];
    int[] b = new int[n];
    for (int i = 0; i < n; i++) {
      a[i] = scanner.nextInt();
    }
    for (int i = 0; i < n; i++) {
      b[i] = scanner.nextInt();
    }
    int sum = 0;
    for (int i = 0; i < n; i++) {
      sum += a[i] * b[i];
    }
    System.out.println(sum);
  }
}