import java.util.Scanner;
import java.util.Stack;
public class intern20191 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(), m = sc.nextInt();
        int [][] board = new int[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                board[i][j] = sc.nextInt();
            }
        }
        int moves[] = new int[m];
        for (int i = 0; i < m; i++) {
            moves[i] = sc.nextInt();
        }
        Solution solution = new Solution();
        System.out.println(solution.solution(board, moves));
    }
}
class Solution {
    public int solution(int[][] board, int[] moves) {
        int answer = 0, n = board.length, m = moves.length;
        Stack<Integer> bucket = new Stack<>();
        Stack<Integer> st[] = new Stack[n + 1];
        for (int i = 1; i <= n; i++) {
            st[i] = new Stack<>();
        }
        for (int i = n - 1; i >= 0; --i) {
            for (int j = 0; j < n; ++j) {
                if(board[i][j] != 0)
                    st[j + 1].push(board[i][j]);
            }
        }
        for (int i = 0; i < moves.length; i++) {
            int next = moves[i];
            if(st[next].isEmpty()) continue;
            int top = st[next].pop();
            if(!bucket.isEmpty() && bucket.peek() == top) {
                bucket.pop();
                answer += 2;
            }
            else bucket.add(top);
        }
        return answer;
    }
}