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.LinkedList;
import java.util.Queue;
import java.util.Stack;
import java.util.StringTokenizer;

public class Main {
	public static void main(String args[]) throws NumberFormatException,IOException {
		
		Stdin in = new Stdin();
		PrintWriter out = new PrintWriter(System.out);
		int n=in.readInt();
		int m=in.readInt();
		int w[]=new int[n];
		int cost=0;
		for(int i=0;i<w.length;i++)
			w[i]=in.readInt();
		int b[]=new int[m];
		LinkedList<Integer>stack=new LinkedList<Integer>();
		LinkedList<Integer>move=new LinkedList<Integer>();
		for(int i=0;i<b.length;i++){
			b[i]=in.readInt()-1;
			if(i>0){
				if(stack.peek()!=b[i]){
					while(!stack.isEmpty()&&stack.peekFirst()!=b[i]){
						cost+=w[stack.peekFirst()];
						move.add(stack.removeFirst());
					}
					if(!stack.isEmpty()&&stack.peekFirst()==b[i])
						move.addFirst(stack.removeFirst());
					else
						move.addFirst(b[i]);
					while(!move.isEmpty())
						stack.addFirst(move.removeLast());
				}				
			}else
				stack.add(b[i]);
			
			
		}
		out.println(cost);
		out.flush();
		out.close();

	}

	private static class Stdin {
		InputStreamReader read;
		BufferedReader br;

		StringTokenizer st = new StringTokenizer("");

		private Stdin() {
			read = new InputStreamReader(System.in);
			br = new BufferedReader(read);

		}

		private String readNext() throws IOException {

			while (!st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		private int readInt() throws IOException, NumberFormatException {

			return Integer.parseInt(readNext());

		}

		private long readLong() throws IOException, NumberFormatException {

			return Long.parseLong(readNext());

		}
	}
}
