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.Scanner;
import java.util.Stack;


public class Bye_2014_1 {
    public static void main(String[] args) throws IOException{
        PrintWriter pw = new PrintWriter(System.out, true);
        BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
        String[] line = input.readLine().split(" ");
        int n = Integer.parseInt(line[0]);
        int m = Integer.parseInt(line[1]);
        int[] W = new int[n];
        line = input.readLine().split(" ");
        for(int i=0;i<n;i++){
            W[i] = Integer.parseInt(line[i]);
        }
        int[] M = new int[m];
        line = input.readLine().split(" ");
        for(int i=0;i<m;i++){
            M[i] = Integer.parseInt(line[i])-1;
        }
        Stack<Integer> A = new Stack<>();
        Stack<Integer> B = new Stack<>();
        boolean[] check = new boolean[n];
        for(int i=0;i<m;i++){
            if(!check[M[i]]){
                check[M[i]] = true;
                B.push(M[i]);
            }
        }
        for(int i=0;i<n;i++){
            if(!check[i]){
                check[i] = true;
                B.push(i);
            }
        }
        while(!B.isEmpty()){
            //System.out.println(B.peek());
            A.push(B.pop());
        }
        int x; 
        long sum = 0;
        for(int i=0;i<m;i++){
            while(A.peek() != M[i])B.push(A.pop());
            x = A.pop();
            
            while(!B.isEmpty()){
                sum += W[B.peek()];
                A.push(B.pop());
            }
            A.push(x);
        }
        pw.println(sum);
        pw.close();
        input.close();
    }
}
