#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define int long long
#define ll long long
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define f first
#define s second
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define imp cout<<-1<<"\n"
#define pb push_back
#define pii pair<int,int>
#define piii pair<int,pair<int,int>>
#define ls v<<1
#define rs v<<1|1
#define fast ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define ptree tree *
const int mod=1e9+7;
const int INF = 1e18;
const int N=1e6+50;
const int logn=16;
void solve(){
int n,q,m,b,c;
cin>>n;
map<int,int>cnt;
vector<int>v(n+1);
for(int i=1;i<=n;i++){
cin>>v[i];
}
vector<int>g(n+1);
for(int i=1;i<=n;i++){
cin>>g[i];
}
vector<int>dp(n+1);
dp[0]=0;
for(int i=1;i<=n;i++){
cnt.clear();
int ans=0;
int mx=-1;
for(int j=i;j>=1;j--){
if(mx==g[j]){
ans++;
}
cnt[g[j]]++;
if(mx<v[j]){
ans-=cnt[mx];
mx=v[j];
ans+=cnt[mx];
}
dp[i]=max(dp[i],ans+dp[j-1]);
}
}
int ans=0;
for(int i=1;i<=n;i++){
ans=max(dp[i],ans);
}
cout<<ans<<"\n";
}
signed main(){
fast;
int t=1;
// cin>>t;
while(t--){
solve();
}
return 0;
}
