#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")
#define int long long
#define F first
#define S second
#define pb push_back
#define endl '\n'
#define all(v) v.begin(),v.end()
#define gcd(a,b) __gcd(a,b)
#define mt make_tuple
#define pqueue priority_queue
typedef pair<int,int> ii;
typedef tuple<int,int,int> iii;
typedef tuple<int,int,int,int> iiii;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<char> vc;
typedef vector<iii> viii;
typedef set<int> si;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<si> vsi;
typedef vector<vb> vvb;
typedef vector<vc> vvc;
const int MOD = 998244353;
const int inf = 3e5;
int32_t main(){
int n; cin >> n;
vi a(n),b(n);
for (int i = 0; i < n; i++) cin >> a[i];
for (int i = 0; i < n; i++) cin >> b[i];
vi dp(n);
for (int i = 0; i < n; i++){
unordered_map<int,int> mp;
int ans = 0,mx = -INT_MAX;
for (int j = i; j > -1; j--){
mx = max(mx,a[j]);
mp[b[j]]++;
ans = max(ans,mp[mx] + (j != 0 ? dp[j-1] : 0));
}
dp[i] = ans;
}
cout << dp[n-1];
return 0;
}
