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.InputStreamReader;
import java.io.PrintWriter;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeSet;

public class NewYearReading {

	public static void main(String[] args) {
		FastScanner scan = new FastScanner();
		PrintWriter out = new PrintWriter(System.out);
		int n = scan.nextInt(), k = scan.nextInt();
		Stack<Book> temp = new Stack<>();
		int[] w = new int[n], o = new int[k];
		for(int i = 0; i < n; i++) w[i] = scan.nextInt();
		TreeSet<Integer> u = new TreeSet<>();
		
		for(int i = 0; i < k; i++){
			int x = scan.nextInt()-1;
			if(!u.contains(x)) temp.push(new Book(x, w[x]));
			u.add(x);
			o[i] = x;
		}
		Stack<Book> s = new Stack<>(), q = new Stack<>();
		while(!temp.isEmpty()) s.push(temp.pop());
		int res = 0;
		for(int i = 0; i < k; i++){
			int idx = o[i];
			int add = 0;
			while(s.peek().i != idx){
				add += s.peek().w;
				q.push(s.pop());
			}
			Book read = s.pop();
			res += add;
			while(!q.isEmpty()) s.push(q.pop());
			s.push(read);
		}
		out.println(res);
		out.close();
	}

	static class Book {
		int i, w;
		public Book(int a, int b){
			i = a;
			w = b;
		}
	}
	
	static class FastScanner {
		BufferedReader br;
		StringTokenizer st;

		public FastScanner() {
			try	{
				br = new BufferedReader(new InputStreamReader(System.in));
				st = new StringTokenizer(br.readLine());
			} catch (Exception e){e.printStackTrace();}
		}

		public String next() {
			if (st.hasMoreTokens())	return st.nextToken();
			try {st = new StringTokenizer(br.readLine());}
			catch (Exception 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());}
		
		public String nextLine() {
			String line = "";
			try {line = br.readLine();} 
			catch (Exception e) {e.printStackTrace();}
			return line;
		}
		
		public int[] nextArray(int n) {
			int[] a = new int[n];
			for(int i = 0; i < n; i++) a[i] = nextInt();
			return a;
		}
	}
	
}
