50 50
75 71 23 37 28 23 69 75 5 62 3 11 96 100 13 50 57 51 8 90 4 6 84 27 11 89 95 81 10 62 48 52 69 87 97 95 30 74 21 42 36 64 31 80 81 50 56 53 33 99
26 30 5 33 35 29 6 15 36 17 32 16 14 1 29 34 22 40 12 42 38 48 39 50 13 47 18 43 10 8 49 45 11 31 21 37 46 28 20 41 2 7 9 24 27 23 3 44 15 14
 10 10
61 59 97 16 2 94 57 48 91 93
2 8 6 5 3 1 3 4 9 10
 2 1
1 2
1
 3 3
10 20 30
1 2 3
 50 60
86 57 45 93 17 12 40 10 47 80 18 80 3 9 6 55 13 99 5 76 4 70 100 55 27 91 71 3 65 93 41 74 80 56 90 50 58 13 71 9 47 52 26 73 72 21 15 81 88 28
40 32 5 16 49 23 3 17 14 10 1 15 1 21 28 22 13 45 12 25 44 48 46 32 36 43 11 8 49 7 7 35 10 14 39 4 42 10 30 27 1 17 31 15 8 41 44 33 25 26 19 18 29 37 50 6 36 38 47 9
 2 7
20 30
1 1 1 2 2 2 2
 2 2
10 12
2 1
 5 1
16 87 36 16 81
3
 2 3
20 30
1 1 1
 2 10
39 26
1 1 2 2 2 2 2 2 1 2

63929
 2137
 0
 40
 62514
 20
 12
 0
 0
 104

#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const long double PI = 4 * atan((long double)1);
const long long int INF = 1e18;
const long long int NINF = -1e18;
long long int get_hash(string s) {
  long long int N = 1000001;
  long long int base[N], A = 11, MD = 1110111110111;
  base[0] = 1;
  for (long long int i = (1); i < (N); ++i) base[i] = (base[i - 1] * A) % MD;
  long long int hs = 0;
  for (long long int i = (0); i < (s.size()); ++i) {
    hs += (s[i] * base[i]);
    hs %= MD;
  }
  return hs;
}
long long power(long long a, long long n) {
  long long res = 1;
  while (n) {
    if (n % 2) res *= a;
    a *= a;
    n /= 2;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  int n, m;
  cin >> n >> m;
  map<int, int> mpc;
  long long int a[n], b[m];
  for (long long int i = (0); i < (n); ++i) cin >> a[i];
  int arr[n];
  map<int, int> mpa, mpb;
  int k = 0;
  for (long long int i = (0); i < (m); ++i) {
    cin >> b[i];
    if (mpa[b[i]] != 1) {
      arr[k] = b[i];
      k++;
      mpa[b[i]] = 1;
    }
  }
  if (k != n) {
    for (long long int i = (1); i < (n + 1); ++i) {
      if (mpa[i] != 1) {
        mpa[i] = 1;
        arr[k] = i;
        k++;
      }
    }
  }
  stack<int> st, st1;
  for (int i = n - 1; i >= 0; i--) st.push(arr[i]);
  long long int ans = 0;
  for (long long int i = (0); i < (m); ++i) {
    int x = b[i];
    while (st.top() != x) {
      st1.push(st.top());
      ans += a[st.top() - 1];
      st.pop();
    }
    st.pop();
    while (!st1.empty()) {
      st.push(st1.top());
      st1.pop();
    }
    st.push(x);
  }
  cout << ans;
  return 0;
}
