#include<bits/stdc++.h>
using namespace std;
#define LL long long  
int n;
int F[3010];
int a[3010];
int b[3010];
void LCIS(){
    memset(F,0,sizeof(F));
    for(int i=1;i<=n;i++){
        LL maxn = 0;
        for(int j=1;j<=n;j++){
            if(a[i] > b[j] && maxn < F[j]) maxn = F[j];
            if(a[i] == b[j]) F[j] = maxn+1; 
        }
    }
    LL maxn = 0;
    for(int i = 1;i<=n;i++){
        if(maxn < F[i]) maxn = F[i]; 
    }
    printf("%lld\n",maxn);
}
int main()
{

    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    for(int i=1;i<=n;i++)
    {
        cin>>b[i];
    }
    LCIS();
    return 0;
}