#include <bits/stdc++.h>
using namespace std;
typedef int ll;
ll INF = 1e9+7;
ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ii,ll>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
int main(void){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll n;
cin>>n;
ll a[n],b[n];
f(i,0,n){
cin>>a[i];
}
f(i,0,n){
cin>>b[i];
}
ll l[n],r[n];
priority_queue<ii,vector<ii>,greater<ii> >pq;
f(i,0,n){
pq.push(ii(a[i],i));
while(pq.top().F < a[i]){
r[pq.top().S] = i-1;
pq.pop();
}
}
while(!pq.empty()){
r[pq.top().S] = n-1;
pq.pop();
}
for(ll i=n-1;i >= 0;i--){
pq.push(ii(a[i],i));
while(pq.top().F < a[i]){
l[pq.top().S] = i+1;
pq.pop();
}
}
while(!pq.empty()){
l[pq.top().S] = 0;
pq.pop();
}
ll dp[n+1][n+1];
f(i,0,n+1){
f(j,0,n+1){
if(i == 0 || j == 0){
dp[i][j] = 0;
}
else{
dp[i][j] = max(dp[i-1][j],dp[i][j-1]);
if(a[i-1] == b[j-1] && (l[i-1] <= j-1 && j-1 <= r[i-1])){
dp[i][j] = max(dp[i][j],dp[i][j-1] + 1);
}
}
}
}
cout<<dp[n][n]<<endl;
}
