// #pragma GCC target("avx2")
#pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
using namespace std;

using P = pair<int, int>;
const int M = 1000000007;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    int n;
    cin >> n;
    vector<int> a(n), mp(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        --a[i];
    }
    for (int i = 0; i < n; ++i) {
        int b;
        cin >> b;
        --b;
        mp[b] = i;
    }
    vector<int> idx(n);
    for (int i = 0; i < n; ++i) {
        a[i] = mp[a[i]];
        idx[a[i]] = i;
    }
    int c = 0;
    for (int i = 0; i + 1 < n; ++i) {
        if (idx[i] > idx[i + 1]) ++c;
    }
    int ans = 0;
    while (c >> ans) ++ans;
    cout << ans << '\n';

    return 0;
}