import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for (int i = 0; i < n; i++) {
		    arr[i] = sc.nextInt();
		}
		int[] order = new int[n + 1];
		for (int i = 0; i < n; i++) {
		    order[sc.nextInt()] = i;
		}
		ArrayList<Integer> list = new ArrayList<>();
		list.add(-1);
		list.add(Integer.MAX_VALUE);
		int count = 0;
		for (int i = 0; i < n; i++) {
		    int x = order[arr[i]];
		    int left = 0;
		    int right = list.size();
		    while (right - left > 1) {
		        int m = (left + right) / 2;
		        if (list.get(m) < x) {
		            left = m;
		        } else {
		            right = m;
		        }
		    }
		    count += list.size() - right - 1;
		    list.add(right, x);
		}
		System.out.println(count);
   }
}