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 cf2014C {
    public static void main(String[] args) throws Exception {
    	// BufferedReader in = new BufferedReader(new FileReader("cf2014C.in"));
    	BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    	
		String str = in.readLine();
		int n = Integer.parseInt(str.substring(0, str.indexOf(" ")));
		int m = Integer.parseInt(str.substring(str.indexOf(" ") + 1));
		
		String[] arr = in.readLine().split(" ");
		
		int[] w = new int[arr.length];
		for(int i = 0; i < w.length; i++) {
			w[i] = Integer.parseInt(arr[i]);
		}
		
		arr = in.readLine().split(" ");
		
		int[] b = new int[arr.length];
		for(int i = 0; i < b.length; i++) {
			b[i] = Integer.parseInt(arr[i]) - 1;
		}
		boolean[] hV = new boolean[n];
		ArrayList<Integer> list = new ArrayList<Integer>();
		for(int i = 0; i < m; i++) {
			if(!hV[b[i]]) {
				hV[b[i]] = true;
				list.add(b[i]);
			}
		}
		for(int i = 0; i < n; i++) {
			if(!hV[i]) {
				list.add(i);
			}
		}
		int[] order = new int[n];
		for(int i = 0; i < n; i++) {
			order[i] = list.get(i);
		}
		long total = 0;
		for(int i = 0; i < m; i++) {
			int search = b[i];
			boolean found = false;
			for(int j = n - 1; j > -1; j--) {
				if(found) {
					total += w[order[j]];
					order[j + 1] = order[j];
				} else {
					if(order[j] == search) {
						found = true;
					}
				}
			}
			order[0] = search;
		}
		System.out.println(total);
	}
}