import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int[] a = new int[n - 1];
    int[] b = new int[n];
    int[] c = new int[n];
    for(int i = 0; i < n - 1; i++) {
      a[i] = sc.nextInt();
    }
    for(int i = 0; i < n; i++) {
      if(i == 0) {
        b[i] = sc.nextInt();
        c[i] = sc.nextInt();
      } else {
        b[i] = (b[i - 1] + sc.nextInt());
        c[i] = (c[i - 1] + sc.nextInt());
      }
    }
    int ans = 0;
    for(int i = 0; i < n - 1; i++) {
      ans += ((a[i]) * (c[i] - b[i]));
    }
  }
}