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.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;

public class C implements Runnable {

    private void solve() throws Exception {
        int n = nextInt();
        int m = nextInt();
        int[] w = new int[n];
        for (int i = 0; i < n; i++) {
            w[i] = nextInt();
        }
        int[] b = new int[m];
        for (int i = 0; i < m; i++) {
            b[i] = nextInt() - 1;
        }
        int ans = 0;
        boolean[] was = new boolean[n];
        for (int i = 0; i < m; i++) {
            Arrays.fill(was, false);
            for (int j = i - 1; j >= 0; j--) {
                if (b[j] == b[i]) {
                    break;
                }
                if (!was[b[j]]) {
                    was[b[j]] = true;
                    ans += w[b[j]];
                }
            }
        }
        out.println(ans);
    }

    private BufferedReader in;
    private StringTokenizer tokenizer = new StringTokenizer("");
    private PrintWriter out;

    private String nextToken() throws IOException {
        while (!tokenizer.hasMoreTokens()) {
            tokenizer = new StringTokenizer(in.readLine());
        }
        return tokenizer.nextToken();
    }

    private int nextInt() throws IOException {
        return Integer.parseInt(nextToken());
    }

    private long nextLong() throws IOException {
        return Long.parseLong(nextToken());
    }

    @Override
    public void run() {
        this.in = new BufferedReader(new InputStreamReader(System.in));
        this.out = new PrintWriter(System.out);
        try {
//            int t = nextInt();
//            for (int c = 0; c < t; c++) {
                solve();
//                out.println();
//            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            out.close();
        }
    }

    public static void main(String[] args) {
        new Thread(new C()).start();
    }

}