#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int N;
  cin >> N;
  vector<int> A(N);
  for (int i = 0; i < N; i++) {
    cin >> A[i];
  }
  vector<int> B(N);
  for (int i = 0; i < N; i++) {
    cin >> B[i];
  }
  vector<int> C(N - 1);
  for (int i = 0; i < N - 1; i++) {
    cin >> C[i];
  }
  int sum = B[A[0] - 1];
  for (int i = 1; i < N; i++) {
    sum += B[A[i] - 1];
    if ((A[i]) != 1) {
      sum += C[A[i] - 2];
    }
  }
  cout << sum << endl;
}
