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.IOException;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author George Marcus
 */
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];
        for (int i = 0; i < N; i++) {
            W[i] = in.nextInt();
        }
        int[] B = new int[M];
        for (int i = 0; i < M; i++) {
            B[i] = in.nextInt();
            B[i]--;
        }

        int[] pos = new int[N];
        Arrays.fill(pos, M);
        for (int i = 0; i < M; i++) {
            int b = B[i];
            if (pos[b] == M) {
                pos[b] = i;
            }
        }

        Book[] books = new Book[N];
        for (int i = 0; i < N; i++) {
            books[i] = new Book(pos[i], i);
        }
        Arrays.sort(books);

        int[] C = new int[N];
        for (int i = 0; i < N; i++) {
            C[i] = books[i].idx;
        }

        long ans = 0;
        for (int i = 0; i < M; i++) {
            int b = B[i];
            int p = -1;
            long sum = 0;
            for (int j = 0; j < N && p == -1; j++) {
                if (C[j] == b) {
                    p = j;
                }
                else {
                    sum += W[C[j]];
                }
            }
            ans += sum;
            for (int j = p - 1; j >= 0; j--) {
                C[j + 1] = C[j];
            }
            C[0] = b;
        }

        out.println(ans);
    }

    private class Book implements Comparable<Book> {
        public int pos;
        public int idx;

        private Book(int pos, int idx) {
            this.pos = pos;
            this.idx = idx;
        }

        public int compareTo(Book o) {
            if (pos != o.pos) {
                return pos - o.pos;
            }
            return idx - o.idx;
        }
    }
}

class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;

    public InputReader(InputStream stream) {
        this.stream = stream;
    }

    public int read() {
        if (numChars == -1)
            throw new InputMismatchException();
        if (curChar >= numChars) {
            curChar = 0;
            try {
                numChars = stream.read(buf);
            } catch (IOException e) {
                throw new InputMismatchException();
            }
            if (numChars <= 0)
                return -1;
        }
        return buf[curChar++];
    }

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

    public String nextString() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        StringBuffer res = new StringBuffer();
        do {
            res.appendCodePoint(c);
            c = read();
        } while (!isSpaceChar(c));

        return res.toString();
    }

    private boolean isSpaceChar(int c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

}

