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.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Stack;

public class TaskC {

	public FasterScanner mFScanner;
	public PrintWriter mOut;
	private int N, M;
	private int[] mBookWeight, mAccessOrder;
	private int[] mBookOrder;
	private HashSet<Integer> mBookOccur;
	private Stack<Integer> mStack;
	private Stack<Integer> mRStack;

	public TaskC() {
		mFScanner = new FasterScanner();
		mOut = new PrintWriter(System.out);
	}

	public void solve() {
		int touchedBooks;
		int bookNum;
		long res = 0;

		N = mFScanner.nextInt();
		M = mFScanner.nextInt();

		mBookWeight = mFScanner.nextIntArray(N);
		mAccessOrder = mFScanner.nextIntArray(M);
		mBookOccur = new HashSet<Integer>();
		mBookOrder = new int[N];
		touchedBooks = 0;

		for (int i = 0; i < M; i++) {
			bookNum = mAccessOrder[i];
			if (mBookOccur.contains(bookNum))
				continue;
			mBookOccur.add(bookNum);

			mBookOrder[touchedBooks++] = bookNum;

		}

		mStack = new Stack<Integer>();
		mRStack = new Stack<Integer>();

		for (int i = touchedBooks - 1; i >= 0; i--) {
			mStack.push(mBookOrder[i]);
		}
		int top;

		for (int i = 0; i < M; i++) {

			bookNum = mAccessOrder[i];
			while (true) {
				top = mStack.pop();
				if (top == bookNum)
					break;
				mRStack.push(top);
				res += mBookWeight[top - 1];
			}
			
			while (!mRStack.isEmpty()) {
				int temp = mRStack.pop();
				mStack.push(temp);
			}
			
			mStack.push(top);

		}
		
		mOut.println(res);

	}

	public void flush() {
		mOut.flush();
	}

	public void close() {
		mOut.close();
	}

	public static void main(String[] args) {
		TaskC mSol = new TaskC();
		mSol.solve();
		mSol.flush();
		mSol.close();
	}

	class FasterScanner {
		private InputStream mIs;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public FasterScanner() {
			this(System.in);
		}

		public FasterScanner(InputStream is) {
			mIs = is;
		}

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = mIs.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public double nextDouble() {
			Double next;
			next = Double.parseDouble(nextString());
			return next;
		}

		public boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		public boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

		public char[] nextCharArray(int N) {
			int i;
			char[] array;
			String str;

			array = new char[N];

			i = 0;

			str = nextLine();

			for (i = 0; i < N && i < str.length(); i++) {
				array[i] = str.charAt(i);
			}

			return array;
		}

		public char[][] nextChar2DArray(int M, int N) {
			int i;
			char[][] array;

			array = new char[M][N];

			i = 0;

			for (i = 0; i < M; i++) {
				array[i] = nextCharArray(N);
			}

			return array;
		}

		public int[] nextIntArray(int N) {
			int i;
			int[] array;

			array = new int[N];

			i = 0;

			for (i = 0; i < N; i++) {
				array[i] = nextInt();
			}

			return array;
		}

		public int[][] nextInt2DArray(int M, int N) {
			int i;
			int[][] array;

			array = new int[M][N];

			i = 0;

			for (i = 0; i < M; i++) {
				array[i] = nextIntArray(N);
			}

			return array;
		}

		public long[] nextLongArray(int N) {
			int i;
			long[] array;

			array = new long[N];

			i = 0;

			for (i = 0; i < N; i++) {
				array[i] = nextLong();
			}

			return array;
		}

		public long[][] nextLong2DArray(int M, int N) {
			int i;
			long[][] array;

			array = new long[M][N];

			i = 0;

			for (i = 0; i < M; i++) {
				array[i] = nextLongArray(N);
			}

			return array;
		}

		public double[] nextDoubleArray(int N) {
			int i;
			double[] array;

			array = new double[N];

			for (i = 0; i < N; i++) {
				array[i] = nextDouble();
			}

			return array;
		}

		public double[][] nextDouble2DArray(int M, int N) {
			int i;
			double[][] array;

			array = new double[M][N];

			for (i = 0; i < M; i++) {
				array[i] = nextDoubleArray(N);
			}

			return array;
		}

	}
}