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

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeSet;

/**
 *
 * @author Reza
 */
public class C {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer strt = new StringTokenizer(br.readLine());
        int n = Integer.parseInt(strt.nextToken());
        int m = Integer.parseInt(strt.nextToken());

        StringTokenizer wstt = new StringTokenizer(br.readLine());
        int wary[] = new int[n];
        for (int i = 0; i < n; i++) {
            int w = Integer.parseInt(wstt.nextToken());
            wary[i] = w;
        }

        TreeSet<Integer> ts = new TreeSet<Integer>();
        ArrayList<Integer> oral = new ArrayList<Integer>();
        StringTokenizer stt1 = new StringTokenizer(br.readLine());
        int mary[] = new int[m];
        for (int i = 0; i < m; i++) {
            int x = Integer.parseInt(stt1.nextToken()) - 1;
            mary[i] = x;
            if (!ts.contains(x)) {
                ts.add(x);
                oral.add(x);
            }
        }
        Stack<Integer> mst = new Stack<Integer>();
        for (int i = oral.size() - 1; i >= 0; i--) {
            mst.add(oral.get(i));
        }

        long sum = 0;
        for (int i = 0; i < m; i++) {
            Stack<Integer> hst = new Stack<Integer>();
            int book = mary[i];
            int sbook;
            while ((sbook = mst.pop()) != book) {
                sum += wary[sbook];
                hst.add(sbook);
            }
            while (!hst.isEmpty()) {
                mst.add(hst.pop());
            }
            mst.add(book);
        }
        System.out.println(sum);

    }
}
