#include <bits/stdc++.h>
using namespace std;
template <typename T>
T Abs(T first) {
  return (first < 0 ? -first : first);
}
template <typename T>
T Sqr(T first) {
  return (first * first);
}
string plural(string s) {
  return (int((s).size()) && s[int((s).size()) - 1] == 'x' ? s + "en"
                                                           : s + "s");
}
const int INF = (int)1e9;
const long double EPS = 1e-9;
const long double PI = acos(-1.0);
bool Read(int &first) {
  char c, r = 0, n = 0;
  first = 0;
  for (;;) {
    c = getchar();
    if ((c < 0) && (!r)) return (0);
    if ((c == '-') && (!r))
      n = 1;
    else if ((c >= '0') && (c <= '9'))
      first = first * 10 + c - '0', r = 1;
    else if (r)
      break;
  }
  if (n) first = -first;
  return (1);
}
bool ReadLL(long long &first) {
  char c, r = 0, n = 0;
  first = 0;
  for (;;) {
    c = getchar();
    if ((c < 0) && (!r)) return (0);
    if ((c == '-') && (!r))
      n = 1;
    else if ((c >= '0') && (c <= '9'))
      first = first * 10 + c - '0', r = 1;
    else if (r)
      break;
  }
  if (n) first = -first;
  return (1);
}
int main() {
  if (0) freopen("in.txt", "r", stdin);
  int N, M;
  int i, j, k, c;
  static int V[1005], ord[1005], ind[1005];
  static pair<int, int> P[1005];
  stack<int> S, S2;
  Read(N), Read(M);
  for (i = 0; i < N; i++) Read(V[i]);
  memset(ind, 60, sizeof(ind));
  for (i = 0; i < M; i++) {
    Read(ord[i]), ord[i]--;
    ind[ord[i]] = min(ind[ord[i]], i);
  }
  for (i = 0; i < N; i++) P[i] = make_pair(ind[i], i);
  sort(P, P + N);
  for (i = (N)-1; i >= 0; i--) S.push(P[i].second);
  long long ans = 0;
  for (i = 0; i < M; i++) {
    j = ord[i];
    while (S.top() != j) ans += V[S.top()], S2.push(S.top()), S.pop();
    S.pop();
    while (!S2.empty()) S.push(S2.top()), S2.pop();
    S.push(j);
  }
  cout << ans << endl;
  return (0);
}
