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

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

class TaskC {
    public void solve(int testNumber, InputReader in, PrintWriter out) {
        int n=in.nextInt();
        int m=in.nextInt();
        int w[]=new int[n];
        int d[]=new int[m];
        in.getArray(w);
        in.getArray(d);
        boolean bookDone[]=new boolean[n];
        Arrays.fill(bookDone,false);
        ArrayList<Integer> stack=new ArrayList<Integer>();
        for(int i=0;i<m;i++){
            if(!bookDone[d[i]-1]){
                stack.add(d[i]);
                bookDone[d[i]-1]=true;
            }
        }
        stack=reverse(stack);
        long ans=0;
        for(int i=0;i<m;i++){
            int bn=d[i];
            int ind=getIndex(stack,bn);
            for(int j=ind+1;j<stack.size();j++){
                ans=ans+(long)(w[stack.get(j)-1]);
            }
            stack.remove(ind);
            stack.add(bn);
        }
        out.print(ans);
    }
    public int getIndex(ArrayList<Integer> stack,int bn){
        for(int i=0;i<stack.size();i++){
            if(stack.get(i)==bn){
                return i;
            }
        }
        return -1;
    }
    public ArrayList<Integer> reverse(ArrayList<Integer> stack){
        ArrayList<Integer> ret=new ArrayList<Integer>();
        for(int i=stack.size()-1;i>=0;i--){
            ret.add(stack.get(i));
        }
        return ret;
    }
}

class InputReader{
    private BufferedReader reader;
    private StringTokenizer tokenizer;

    public InputReader(InputStream stream){
        reader = new BufferedReader(new InputStreamReader(stream));
        tokenizer = null;
    }
    public String next(){
        while (tokenizer == null||!tokenizer.hasMoreTokens()){
            try{
                tokenizer = new StringTokenizer(reader.readLine());
            }
            catch (IOException e){
                throw new RuntimeException(e);
            }

            catch (NullPointerException e){
                throw new UnknownError();
            }
        }
        return tokenizer.nextToken();
    }

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

    public void getArray(int arr[]){
        for(int i=0;i<arr.length;i++){
            arr[i]=nextInt();
        }
    }

}

