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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Set;
import java.util.Stack;
import java.util.StringTokenizer;

public class C {

    public static void main(String[] args) {
        InputScanner is = new InputScanner();
        try {
            int n, m;
            n = is.nextInt();
            m = is.nextInt();
            int[] weight = new int[n];
            int[] books = new int[m];
            for (int i = 0; i < n; i++) weight[i] = is.nextInt();
            for (int i = 0; i < m; i++) books[i] = is.nextInt();

            Stack<Integer> stack = new Stack<>();
            Set<Integer> set = new HashSet<>();

            for (int i = 0; i < m; i++) {
                int book = books[i];
                if (!set.contains(book)) {
                    set.add(book);
                    stack.push(book);
                }
            }

            Stack<Integer> reversedStack = new Stack<>();
            Stack<Integer> tmpStack = new Stack<>();

            while(!stack.isEmpty())
                reversedStack.push(stack.pop());

            int result = 0;
            for (int i = 0; i < m; i++){
                int bookNr = books[i];
                while(reversedStack.peek()!=bookNr){
                    tmpStack.push(reversedStack.pop());
                    result += weight[tmpStack.peek()-1];
                }
                int b = reversedStack.pop();
                while(!tmpStack.isEmpty()){
                    reversedStack.push(tmpStack.pop());
                }
                reversedStack.push(b);
            }
            System.out.println(result);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    static class InputScanner {

        BufferedReader br;
        StringTokenizer st;

        public InputScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

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

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

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