/* -*- coding: utf-8 -*-
 *
 * 1922.cc:  No.1922 Separate and Attach - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 100000;

/* typedef */

/* global variables */

int ps[MAX_N], rqs[MAX_N], as[MAX_N];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);

  for (int i = 0; i < n; i++) scanf("%d", ps + i), ps[i]--;

  for (int i = 0; i < n; i++) {
    int qi;
    scanf("%d", &qi), qi--;
    rqs[qi] = i;
  }

  for (int i = 0; i < n; i++) as[rqs[ps[i]]] = i;
  //for (int i = 0; i < n; i++) printf("%d ", as[i]); putchar('\n');

  int l = 1;
  for (int i = 0; i + 1 < n; i++)
    if (as[i] > as[i + 1]) l++;

  int c = 0;
  while (l > 1) {
    l = (l + 1) / 2;
    c++;
  }

  printf("%d\n", c);
  return 0;
}