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.InputStream;
import java.io.InputStreamReader;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Problems problems = new Problems();
        problems.solve();
    }
}

class Problems {

    Parser parser = new Parser();

    void solve() {
        int t = 1;
        for (int i = 0; i < t; i++) {
            Problem problem = new Problem();
            problem.solve(i);
        }
    }

    class Problem {

        int n;
        int m;

        int[] w;
        int[] b;
        int[] prev;

        void solve(int testcase) {
            n = parser.parseInt();
            m = parser.parseInt();

            prev = new int[n + 1];

            w = new int[n + 1];
            for (int i = 1; i <= n; i++) {
                w[i] = parser.parseInt();
            }

            b = new int[m + 1];
            for (int i = 1; i <= m; i++) {
                b[i] = parser.parseInt();
            }

            long ans = 0;
            for (int i = 1; i <= m; i++) {
                int v = b[i];
                ans += calcCost(v);
                prev[v] = i;
            }

            System.out.println(ans);
        }

        int calcCost(int v) {
            int result = 0;
            for(int i = 1; i <= n; i++) {
                if(prev[i] <= prev[v]) {
                    continue;
                }
                result += w[i];
            }
            return result;
        }
    }
}

class Parser {
    private final Iterator<String> stringIterator;
    private final Deque<String> inputs;

    Parser() {
        this(System.in);
    }

    Parser(InputStream in) {
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
        stringIterator = br.lines().iterator();
        inputs = new ArrayDeque<>();
    }

    void fill() {
        while (inputs.isEmpty()) {
            if (!stringIterator.hasNext()) throw new NoSuchElementException();
            inputs.addAll(Arrays.asList(stringIterator.next().split(" ")));
            while (!inputs.isEmpty() && inputs.getFirst().isEmpty()) {
                inputs.removeFirst();
            }
        }
    }

    Integer parseInt() {
        fill();
        if (!inputs.isEmpty()) {
            return Integer.parseInt(inputs.pollFirst());
        }
        throw new NoSuchElementException();
    }

    Long parseLong() {
        fill();
        if (!inputs.isEmpty()) {
            return Long.parseLong(inputs.pollFirst());
        }
        throw new NoSuchElementException();
    }

    Double parseDouble() {
        fill();
        if (!inputs.isEmpty()) {
            return Double.parseDouble(inputs.pollFirst());
        }
        throw new NoSuchElementException();
    }

    String parseString() {
        fill();
        return inputs.removeFirst();
    }
}