#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j, sum;
  cin >> n;
  int a[n], b[n], c[n];
  for (i = 1; i <= n; i++) cin >> a[i];
  for (i = 1; i <= n; i++) cin >> b[i];
  for (i = 1; i < n; i++) cin >> c[i];
  sum = b[a[1]];
  for (i = 2; i <= n; i++) {
    if (a[i] > a[i - 1])
      sum += b[a[i]] + c[a[i - 1]];
    else
      sum += b[a[i]];
  }
  cout << sum << endl;
  return 0;
}
