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.util.HashSet;
import java.util.LinkedList;

/**
 * Created by Tejas on 25-09-2018.
 */
public class Main {

    static int a[],w[];
    public static void main(String[]args)throws IOException{
        BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(System.in));
        String temp[]=bufferedReader.readLine().split(" ");
        int N=Integer.parseInt(temp[0]);
        int M=Integer.parseInt(temp[1]);
        temp=bufferedReader.readLine().split(" ");
        w=new int[N];
        a=new int[M];
        for(int i=0;i<N;i++)
            w[i]=Integer.parseInt(temp[i]);
        temp=bufferedReader.readLine().split(" ");
        for (int i = 0; i < M; i++)
            a[i]=Integer.parseInt(temp[i]);
        System.out.println(solve(N, M));
    }

    private static long solve(int N, int M) {
        HashSet<Integer> set=new HashSet<>();
        LinkedList<Integer> res=new LinkedList<>();
        for(int i=0;i<M;i++) {
            if(set.size()==N) break;
            if (!set.contains(a[i])){
                set.add(a[i]);
                res.add(a[i]);
            }
        }

        long ans=0;
        for(int i=0;i<M;i++){
            int index=res.indexOf(a[i]);
            for(int j=0;j<index;j++)
                ans+=w[a[i]-1];
            res.remove(index);
            res.addFirst(a[i]);
        }
        return ans;
    }
}
