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.InputStreamReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.Arrays;
import java.io.BufferedWriter;
import java.util.ArrayList;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.util.StringTokenizer;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        OutputWriter out = new OutputWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }
}

class TaskC {
    public void solve(int testNumber, InputReader in, OutputWriter out) {
        int n=in.nextInt(),m=in.nextInt();
        int w[]=new int [n+1];
        int q[]=new int [m+1];
        for(int i=1;i<=n;i++){
            w[i]=in.nextInt();
        }
        int q1[]=new int [m],cou=0;
        q[0]=0;
        for(int i=1;i<=m;i++){
            q[i]=in.nextInt();
            if(q[i]!=q[i-1])
                q1[cou++]=q[i];
        }
        long ans=0;
        ArrayList<Integer> stack=new ArrayList<Integer>();
        int done[]=new int [n+1];
        Arrays.fill(done,0);
        int k=0;
        for(int i=0;i<cou;i++){
            if(done[q1[i]]==0){
                stack.add(k++,q1[i]);
                done[q1[i]]++;
            }
        }
        /**for(int i=0;i<k;i++){
            out.print(stack.get(i));
        }*/
        for(int i=1;i<m;i++){
            int tmp=0;
            for(int j=0;j<k;j++){
                if(stack.get(j)==q1[i]){
                    ans+=tmp;
                    //out.print(i+" "+tmp+" ");
                    tmp=stack.remove(j);
                    stack.add(0,tmp);
                    break;
                }
                else tmp+=w[stack.get(j)];
            }
            /**out.printLine();
            for(int i1=0;i1<k;i1++){
                out.print(stack.get(i1));
             }
            out.printLine();

            //ans+=tmp;*/
        }
        out.printLine(ans);
    }
}

class InputReader {
    BufferedReader in;
    StringTokenizer tokenizer=null;

    public InputReader(InputStream inputStream)
    {
        in=new BufferedReader(new InputStreamReader(inputStream));
    }
    public String next()
    {
        try{
            while (tokenizer==null||!tokenizer.hasMoreTokens())
            {
                tokenizer=new StringTokenizer(in.readLine());
            }
            return tokenizer.nextToken();
        }
        catch (IOException e)
        {
            return null;
        }
    }
    public int nextInt()
    {
        return Integer.parseInt(next());
    }
}

class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

    public void print(Object...objects) {
            for (int i = 0; i < objects.length; i++) {
                if (i != 0)
                    writer.print(' ');
                writer.print(objects[i]);
            }
        }

        public void printLine(Object...objects) {
            print(objects);
            writer.println();
        }

        public void close() {
            writer.close();
        }
}
