#include<bits/stdc++.h>

using namespace std;
using ll = long long;


int main()
{
    int n; cin >> n;
    int cnt = 0;
    vector<int> a(n), b(n);
    for(int i = 0; i < n; i++)cin >> a[i];
    for(int i = 0; i < n; i++)cin >> b[i];
    for(int i = 0; i < n;) {
        int j = i;
        while(j < n && a[j] != b[j])j++;
        if(i != j)cnt++, i = j;
        else i++;
    }
    cout << cnt << endl;
}