#include <bits/stdc++.h>
int main() {
  int num = 0;
  scanf("%d", &num);
  int buffet[num], satis[num], add[num - 1];
  scanf("%d", buffet);
  scanf("%d", satis);
  scanf("%d", add);
  int i = 0, ans = 0;
  ans += satis[buffet[0]];
  for (i = 1; i < num; i++) {
    ans += satis[buffet[i]];
    if (buffet[i - 1] == buffet[i] - 1) {
      ans += add[buffet[i]];
    }
  }
  printf("%d", ans);
  return 0;
}
