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

import java.lang.*;
import java.util.*;
import java.io.*;

public class Template {

  public static void main(String[] args) throws Exception {
    InputReader reader = new InputReader(System.in);
    PrintWriter writer = new PrintWriter(System.out, true);
    try {
      new Solution(reader, writer).run();
    } finally {
      reader.close();
      writer.close();
    }
  }
}


class Solution {
  private InputReader reader;
  private PrintWriter writer;

  Solution(InputReader reader, PrintWriter writer) {
    this.reader = reader;
    this.writer = writer;
  }

  public void run() throws Exception {
    int n = reader.nextInt();
    int m = reader.nextInt();

    int[] ws = new int[n];
    for (int i=0; i < n; i++) {
      ws[i] = reader.nextInt();
    }

    int[] bs = new int[m];
    long[] sums = new long[m];
    for (int i=0; i < m; i++) {
      bs[i] = reader.nextInt();
      //;sums[i] = (0 != i ? sums[i-1] : 0) + ws[bs[i] - 1];
    }
    long result = 0;
    for (int j = m -1; j >=0; j--) {
      Set<Integer> visited = new TreeSet<Integer>();
      for (int k = j - 1; k>=0; k--) {
        if (bs[k] == bs[j]) break;
        if (!visited.contains(bs[k])) {
          visited.add(bs[k]);
          result += ws[bs[k] -1];

        }
      }
    }
    writer.println(result);
  }
}

class InputReader {
  private BufferedReader reader;
  private StringTokenizer tokenizer;

  InputReader(InputStream inputStream) {
    this.reader = new BufferedReader(new InputStreamReader(inputStream));
  }

  protected String nextToken() throws Exception {
    while (null == tokenizer || !tokenizer.hasMoreTokens()) {
      this.tokenizer = new StringTokenizer(reader.readLine());
    }
    return tokenizer.nextToken();
  }

  public int nextInt() throws Exception {
    return Integer.parseInt(nextToken());
  }

  public int read() throws Exception {
    int ch = reader.read();
    while (Character.isWhitespace(ch)) {
      ch = reader.read();
    }
    return ch;
  }
  public void close() throws Exception {
    reader.close();
  }
}
