#include<bits/stdc++.h>
using namespace std;
int n,a[10001],k[10001],f[10001][10001]; 
int main()
{
	cin >> n;
	for (int i=1;i<=n;i++)
	{
		cin >> a[i];
	}
	for (int i=1;i<=n;i++)
	{
		cin >> k[i];
	}
	for (int i=1;i<=n;i++)
	{
		for (int j=1;j<=n;j++)
		{
			if (a[i] == k[j])
			{
				f[i][j] = max(f[i][j],f[i-1][j-1]+1);
			}
			else
			{
				f[i][j] = max(f[i-1][j],f[i][j-1]);
			}
		}
	}
	cout << f[n][n];
	return 0;
}