#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
long long  f[10005][10005];
int x[10005],y[10005]; 
int n;
int main()
{	
	cin>>n;
	for(int i = 1 ;i <= n;i++){
		cin>>x[i];
	}
	for(int i = 1 ;i <= n;i++){
		cin>>y[i];
	}
	for(int i = 1;i<=n;i++){
		for(int j = 1;j<=n;j++){
			if(x[i] == y[j]){
				f[i][j] = max(max(f[i-1][j],f[i][j-1]),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;
}