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.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

public class Main {

    IIO io;

    Main(IIO io) {
        this.io = io;
    }

    public static void main(String[] args) throws IOException {
//
        Main m = new Main(new ConsoleIO());
        m.solve();

//        Tester test = new Tester();
//        test.run();
    }

    public void solve() {
        int[] a = io.readIntArray();
        int n = a[0];
        int m = a[1];
        int[] ws = io.readIntArray();
        int[] order = io.readIntArray();

        boolean[] vis = new boolean[n];
        int[] stack = new int[m];
        int tail = m-1;
        for(int i = 0;i<order.length;i++){
            int k = order[i]-1;
            if(vis[k])
                continue;
            stack[tail--] = k;
        }
        int head = m - 1;
        int res = 0;
        int[] second = new int[m];
        int secondHead = 0;
        for(int i = 0;i<order.length;i++) {
            int k = order[i] - 1;
            for (; ; ) {
                int t = stack[head--];
                if (t == k)
                    break;
                res+=ws[t];
                second[secondHead++] = t;
            }
            for (; secondHead > 0; ) {
                int t = second[--secondHead];
                stack[++head] = t;
            }
            stack[++head] = k;
        }

        io.writeLine(Integer.toString(res));
    }


}

class ConsoleIO extends BaseIO {
    BufferedReader br;

    public ConsoleIO(){
        br = new BufferedReader(new InputStreamReader(System.in));
    }

    public void writeLine(String s) {
        System.out.println(s);
    }

    public String readLine() {
        try {
            return br.readLine();
        }
        catch (Exception ex){
            return "";
        }
    }
}
abstract class BaseIO implements IIO {
    @Override
    public int readInt() {
        return Integer.parseInt(this.readLine());
    }

    @Override
    public int[] readIntArray() {
        String line = this.readLine();
        String[] nums = line.split(" ");
        int[] res = new int[nums.length];
        for (int i = 0; i < nums.length; i++) {
            res[i] = Integer.parseInt(nums[i]);
        }
        return res;
    }
}
interface IIO {
    void writeLine(String s);
    String readLine();
    int readInt();
    int[] readIntArray();
}

