#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, x = 0, A[100000], B[100000], C[100000], sum = 0, a = 0;
  cin >> N;
  sum = 0;
  for (int i = 1; i <= N; i++) cin >> A[i];
  for (int i = 1; i <= N; i++) cin >> B[i];
  for (int i = 1; i <= N - 1; i++) cin >> C[i];
  for (int i = 1; i <= N; i++) {
    x = A[i];
    sum += B[x];
  }
  for (int i = 1; i < N; i++) {
    if (A[i] < A[i + 1]) {
      a = A[i];
      sum += C[a];
    }
  }
  cout << sum << endl;
}
