#include <bits/stdc++.h>
using namespace std;
int w[505], p[1005], t[5001], was[105];
int main() {
  int a, b, c, d, f = 0, n, m, x, y, i, j;
  memset(was, 0, sizeof was);
  memset(t, 0, sizeof t);
  scanf("%d %d", &n, &m);
  for (a = 1; a <= n; a++) scanf("%d", &w[a]);
  for (a = 1; a <= m; a++) scanf("%d", &p[a]);
  t[1] = p[1];
  d = 2;
  for (a = 2; a <= m; a++) {
    y = 0;
    for (i = 1; i < d; i++) {
      if (t[i] == p[a]) {
        for (b = i; b > 1; b--) {
          t[b] = t[b - 1];
          f += w[t[b]];
        }
        t[1] = p[a];
        y = 1;
        break;
      }
    }
    if (y == 0) {
      for (b = d; b > 1; b--) {
        t[b] = t[b - 1];
        f += w[t[b]];
      }
      t[1] = p[a];
      d++;
    }
  }
  printf("%d\n", f);
  return 0;
}
