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.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.Stack;

public class C500 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        int weight[] = new int[n + 1];
        int pos[] = new int[n + 1];
        for (int i = 1; i <= n; ++i) {
            weight[i] = in.nextInt();
        }

        int[] read = new int[n + 1];
        int index = 1;
        List<Integer> list = new ArrayList<Integer>();
        int[] days = new int[m];
        for (int i = 0; i < m; ++i) {
            int b = in.nextInt();
            days[i] = b;
            if (read[b] == 0) {
                read[b] = index++;
                list.add(b);
            }
        }
        int size = list.size();
        Stack<Integer> stack = new Stack<>();
        for (int i = size - 1; i >= 0; --i) {
            stack.push(list.get(i));
        }

        long total = 0;
        Stack<Integer> temp = new Stack<>();
        for (int i = 0; i < m; ++i) {
            while (true) {
                int book = stack.pop();
                if (book == days[i]) {
                    break;
                }
                total += weight[book];
                temp.add(book);
            }
            while (!temp.empty()) {
                stack.add(temp.pop());
            }
            stack.add(days[i]);
        }
        System.out.println(total);
    }
}
