#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  vector<int> w(n);
  for (int i = 0; i < n; i++) cin >> w[i];
  int x = 0;
  vector<int> ord(n);
  vector<int> rd(m);
  vector<bool> put(n, false);
  for (int i = 0; i < m; i++) {
    cin >> rd[i];
    rd[i]--;
    if (put[rd[i]])
      continue;
    else {
      ord[x] = rd[i];
      put[rd[i]] = true;
      x++;
    }
  }
  for (int i = 0; i < n; i++) {
    if (!put[i]) {
      ord[x] = i;
      x++;
    }
  }
  int lift = 0;
  for (int i = 0; i < m; i++) {
    int in = 0;
    for (int j = 0; j < n; j++) {
      if (ord[j] == rd[i]) {
        in = j;
      }
    }
    for (int j = in; j > 0; j--) {
      ord[j] = ord[j - 1];
      lift += w[ord[j]];
    }
    ord[0] = rd[i];
  }
  cout << lift << endl;
}
