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

public class nybr {
  private static Reader in;
  private static PrintWriter out;
  
  static class Book implements Comparable<Book> {
    public int a, b;
    public Book(int a, int b) {
      this.a = a;
      this.b = b;
    }
    public int compareTo(Book other) {
      return b - other.b;
    }
  }

  public static void main(String[] args) throws IOException {
    in = new Reader();
    out = new PrintWriter(System.out, true);
    int N = in.nextInt();
    int M = in.nextInt();
    
    int[] w = new int[N];
    for (int i = 0; i < N; i++) {
      w[i] = in.nextInt();
    }
    
    int[] arr = new int[M];
    for (int j = 0; j < M; j++) {
      arr[j] = in.nextInt()-1;
    }
    
    long tot = 0;
    for (int i = 0; i < N; i++)
      for (int j = i+1; j < N; j++) {
        int top = -1;
        for (int k = 0; k < M; k++) {
          if (arr[k] != i && arr[k] != j) continue;
          if (top == -1) {
            top = arr[k];
            continue;
          }
          if (arr[k] == i && top == j) {
            top = i;
            tot += w[j];
          } else if (arr[k] == j && top == i) {
            top = j;
            tot += w[i];
          }
        }
      }
    
    out.println(tot);
    out.close();
    System.exit(0);
  }

  static class Reader {
    final private int BUFFER_SIZE = 1 << 16;
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;

    public Reader() {
      din = new DataInputStream(System.in);
      buffer = new byte[BUFFER_SIZE];
      bufferPointer = bytesRead = 0;
    }

    public Reader(String file_name) throws IOException {
      din = new DataInputStream(new FileInputStream(file_name));
      buffer = new byte[BUFFER_SIZE];
      bufferPointer = bytesRead = 0;
    }

    public String readLine() throws IOException {
      byte[] buf = new byte[1024];
      int cnt = 0;
      byte c = read();
      while (c <= ' ')
        c = read();
      do {
        buf[cnt++] = c;
      } while ((c = read()) != '\n');
      return new String(buf, 0, cnt);
    }

    public String next() throws IOException {
      byte[] buf = new byte[1024];
      int cnt = 0;
      byte c = read();
      while (c <= ' ')
        c = read();
      do {
        buf[cnt++] = c;
      } while ((c = read()) > ' ');
      return new String(buf, 0, cnt);
    }

    public int nextInt() throws IOException {
      int ret = 0;
      byte c = read();
      while (c <= ' ')
        c = read();
      boolean neg = (c == '-');
      if (neg)
        c = read();
      do {
        ret = ret * 10 + c - '0';
      } while ((c = read()) >= '0' && c <= '9');
      if (neg)
        return -ret;
      return ret;
    }

    public long nextLong() throws IOException {
      long ret = 0;
      byte c = read();
      while (c <= ' ')
        c = read();
      boolean neg = (c == '-');
      if (neg)
        c = read();
      do {
        ret = ret * 10 + c - '0';
      } while ((c = read()) >= '0' && c <= '9');
      if (neg)
        return -ret;
      return ret;
    }

    public double nextDouble() throws IOException {
      double ret = 0, div = 1;
      byte c = read();
      while (c <= ' ')
        c = read();
      boolean neg = (c == '-');
      if (neg)
        c = read();
      do {
        ret = ret * 10 + c - '0';
      } while ((c = read()) >= '0' && c <= '9');
      if (c == '.')
        while ((c = read()) >= '0' && c <= '9')
          ret += (c - '0') / (div *= 10);
      if (neg)
        return -ret;
      return ret;
    }

    private void fillBuffer() throws IOException {
      bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
      if (bytesRead == -1)
        buffer[0] = -1;
    }

    private byte read() throws IOException {
      if (bufferPointer == bytesRead)
        fillBuffer();
      return buffer[bufferPointer++];
    }

    public void close() throws IOException {
      if (din == null)
        return;
      din.close();
    }
  }


}
