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.*;
import java.util.*;

public class C {

	BufferedReader in;
	StringTokenizer st;
	PrintWriter out;

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

	int nextInt() throws Exception {
		return Integer.parseInt(next());
	}

	long nextLong() throws Exception {
		return Long.parseLong(next());
	}

	double nextDouble() throws Exception {
		return Double.parseDouble(next());
	}

	void solve() throws Exception {
		int b = nextInt();
		int n = nextInt();

		int w[] = new int[b];
		for (int i = 0; i < b; i++)
			w[i] = nextInt();

		int ro[] = new int[n];
		for (int i = 0; i < n; i++)
			ro[i] = nextInt() - 1;

		boolean u[] = new boolean[b];

		int o[] = new int[b];
		int c = 0;
		for (int i = 0; i < n; i++)
			if (!u[ro[i]]) {
				o[c] = ro[i];
				c++;
				u[ro[i]] = true;
			}

		//System.err.println(Arrays.toString(o));

		int ans = 0;

		for (int i = 0; i < n; i++) {
			int req = ro[i];
			int j = 0, cw = 0;
			//System.err.println(req);
			while (o[j] != req) {
				cw += w[o[j]];
				j++;
			}

			//System.err.println(j);
			
			ans += cw;

			for (int jj = j; jj >= 1; jj--)
				o[jj] = o[jj - 1];
			o[0] = req;

			//System.err.println(Arrays.toString(o));
		}

		out.println(ans);

	}

	void run() {
		try {
			Locale.setDefault(Locale.US);
			in = new BufferedReader(new InputStreamReader(System.in));
			out = new PrintWriter(new OutputStreamWriter(System.out));
			solve();
			out.close();
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

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

}
