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.StringTokenizer;

public class GB2014C {
	private FastScanner in;
	private PrintWriter out;

	public void solve() throws IOException {
		int n = in.nextInt();
		int m = in.nextInt();
		int[] weight = new int[505];
		int[] days = new int[1005];
		boolean[] seen = new boolean[505];
		long res = 0;
		for (int i = 0; i < n; i++){
			weight[i] = in.nextInt();
		}
		for (int i = 0; i < m; i++){
			days[i] = in.nextInt() - 1;
		}
		for (int i = 0; i < m; i++){	
			for (int a = 0; a < 505; a++){ seen[a] = false; }
			outerloop:
			for (int j = i-1; j >= 0; j--){
				if (days[i] == days[j]){ break outerloop; }
				if (seen[days[j]]){ continue; }
				res += weight[days[j]];
				seen[days[j]] = true;
			}
		}
		out.println(res);
	}
	
	public static void main(String[] args) {
		new GB2014C().run();
	}

	public void run() {
		try {
			in = new FastScanner();
			out = new PrintWriter(System.out);
			solve();
			out.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	private class FastScanner {
		private BufferedReader br;
		private StringTokenizer st;

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

		public String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

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

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

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