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.OutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.InputMismatchException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskC solver = new TaskC();
		solver.solve(1, in, out);
		out.close();
	}
}

class TaskC {
    public void solve(int testNumber, InputReader in, PrintWriter out) {
        int n = in.nextInt();
        int m = in.nextInt();

        int [] w= new int[n];

        int [] b = new int[m];

        for(int i=0;i<n;i++) {
            w[i] = in.nextInt();
        }

        for(int i = 0;i<m;i++) {
            b[i] = in.nextInt();
        }

        boolean read []= new boolean[n+1];
        int ksum = 0;

        for(int i=0;i<m;i++) {
             int sum = 0;
             boolean was[] = new boolean[n];
             for(int k=i-1;k>=0;k--) {
                 if(b[k] == b[i])
                     break;
                 if(!was[b[k]-1]) {
                     sum += w[b[k] - 1];
                 }
                 was[b[k]-1] = true;
             }
            ksum += sum;
        }
        out.println(ksum);
    }
}

class InputReader {

    private InputStream stream;
    int curCharIndex = 0;
    int charsInBuf = 0;
     byte buf[] = new byte[16*1024];

    public InputReader(InputStream stream) {
        this.stream = stream;
    }


    public int readChar() {

        if (curCharIndex >= charsInBuf) {
            curCharIndex = 0;
            try {
                charsInBuf = stream.read(buf);
            } catch (IOException e) {
                throw new InputMismatchException();
            }
            if (charsInBuf <= 0)
                return -1;
        }
        return buf[curCharIndex++];
    }


    public int nextInt() {

        int c;
        do {
            c = readChar();
        }while(isWhitespace(c));

        int sign = 1;
        if (c == '-') {
            c = readChar();
            sign = -1;

        }
        int res = 0;
        do {
            res *= 10;
            res += c - '0';
            c = readChar();
        } while (!isWhitespace(c) && c!=-1);
        return sign * res;
    }


    /*
    * For the purpose of compatibilty with Chelper Chrome extension
     */


    private boolean isWhitespace(int c) {
        return  c==' ' || c=='\n'|| c=='\r' || c=='\t';
    }
}

