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.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Stack;
import java.util.StringTokenizer;

public class NewYEarBookReading {

	public static void main(String[] args) throws NumberFormatException, IOException {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();

		int w[] = new int[n];
		for (int i = 0; i < n; i++)
			w[i] = sc.nextInt();
		boolean[] seen = new boolean[n];
		ArrayList<Integer> l = new ArrayList<Integer>();
		Stack<Integer> s = new Stack<Integer>();
		Stack<Integer> s2 = new Stack<Integer>();

		for (int i = 0; i < m; i++) {
			int b = sc.nextInt() - 1;
			if (!seen[b]) {
				seen[b] = true;
				s2.push(b);
			}
			l.add(b);
		}
		while (!s2.isEmpty())
			s.push(s2.pop());
		int min = 0;
		for (int i = 0; i < l.size(); i++) {
			int cur = l.get(i);
			Stack<Integer> temp = new Stack<Integer>();
			while (true) {
				int popped = s.pop();
				if (cur == popped) {
					while (!temp.isEmpty()) {
						s.push(temp.pop());
						min += w[s.peek()];
					}
					s.push(popped);
					break;
				}
				temp.add(popped);
			}
		}

		System.out.println(min);

	}

	static class Scanner {
		BufferedReader br;
		StringTokenizer st;

		public boolean ready() throws IOException {
			return br.ready();
		}

		Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

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

		int nextInt() throws NumberFormatException, IOException {
			return Integer.parseInt(next());
		}

	}
}
