import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
 
 
/* IMPORTANT: Multiple classes and nested static classes are supported */
 
/*
 * uncomment this if you want to read input.
import java.io.BufferedReader;
import java.io.InputStreamReader;
*/
 
 
class TestClass {
    public static void main(String args[] ) throws Exception {
        /*
         * Read input from stdin and provide input before running
 
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line = br.readLine();
        int N = Integer.parseInt(line);
        for (int i = 0; i < N; i++) {
            System.out.println("hello world");
        }
        */
 
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        Queue<Integer> queue = new LinkedList<Integer>();
        for(int i=0;i<n;i++){
        	queue.add(sc.nextInt());
        }
        int[] correct = new int[n];
        for(int i=0;i<n;i++){
        	correct[i] = sc.nextInt();
        }
        int time = 0;
        for(int i=0;i<n;i++){
        	int num = correct[i];
        	int a;
        	while((a = queue.poll())!=num){
        		queue.add(a);
        		time++;
        	}
        	time++;
        }
        System.out.println(time);
 
    }
}