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.*;

/**
 * Created by aa on 1/06/2016.
 */
public class A {


    static long x1 , x2;
    public static void main(String [] args) throws  Exception
    {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        StringBuilder sb = new StringBuilder();
        int n = sc.nextInt() , m = sc.nextInt();
        int w []  = new int[n];
        for(int i = 0 ; i < n ; ++i) w[i] = sc.nextInt();
        Queue<Integer> queue = new LinkedList<>();
        int b [] = new int[m];
        HashSet<Integer> hs = new HashSet<>();
        for(int i = 0 ; i < m ; ++i){b[i] = sc.nextInt(); if(!hs.contains(b[i])) {queue.add(b[i]);hs.add(b[i]);}}
        long cnt = 0;
        for(int i = 0 ; i < m ; ++i)
        {
            Queue<Integer> tmp = new LinkedList<>();
            while(true)
            {
                int cur = queue.poll();
                if(cur == b[i]) break;
                else cnt +=w[cur-1];
                tmp.add(cur);
            }
            while (!queue.isEmpty())tmp.add(queue.poll());
            queue.add(b[i]);
            while (!tmp.isEmpty()) queue.add(tmp.poll());
        }
        out.printf("%d" , cnt);
        out.flush();
        out.close();
    }



    static class Line implements  Comparable<Line>{
        long y1 , y2 ;
        public Line(long slope , long yIntercept)
        {
            y1 = slope * x1 + yIntercept;
            y2 = slope * x2 + yIntercept;
        }

        @Override
        public int compareTo(Line o) {
            if(y1 == o.y1)
                return o.y2 - y2 > 0 ? 1 : -1 ;
            return (o.y1 - y1) >0 ? 1:-1;
        }
    }

    static class Scanner
    {
        StringTokenizer st;
        BufferedReader br;

        public Scanner(InputStream s){	br = new BufferedReader(new InputStreamReader(s));}

        public String next() throws IOException
        {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

        public int nextInt() throws IOException {return Integer.parseInt(next());}

        public long nextLong() throws IOException {return Long.parseLong(next());}

        public String nextLine() throws IOException {return br.readLine();}

        public double nextDouble() throws IOException
        {
            String x = next();
            StringBuilder sb = new StringBuilder("0");
            double res = 0, f = 1;
            boolean dec = false, neg = false;
            int start = 0;
            if(x.charAt(0) == '-')
            {
                neg = true;
                start++;
            }
            for(int i = start; i < x.length(); i++)
                if(x.charAt(i) == '.')
                {
                    res = Long.parseLong(sb.toString());
                    sb = new StringBuilder("0");
                    dec = true;
                }
                else
                {
                    sb.append(x.charAt(i));
                    if(dec)
                        f *= 10;
                }
            res += Long.parseLong(sb.toString()) / f;
            return res * (neg?-1:1);
        }

        public boolean ready() throws IOException {return br.ready();}


    }
}
