#include <iostream>
#include <fstream>
#include <cmath>  
#include <cstdlib>
#include <ctime>
#include <algorithm>
#include <numeric>
#include <functional>
#include <string> 
#include <vector>
#include <bitset>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>

using namespace std;
using ll = long long;

#define REP(i,n) for(long long i = 0; i < (n); i++)
#define FOR(i, m, n) for(long long i = (m);i < (n); ++i)
#define ALL(obj) (obj).begin(),(obj).end()

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;

const ll MOD = (ll)1e9 + 7;
const ll HINF = (ll)1e18;
const ll LINF = (ll)1e9;
const long double PI = 3.1415926535897932384626433;

template <class T> void corner(bool flg, T hoge) { if (flg) { cout << hoge << endl; exit(0); } }
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) { o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o; }
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) { o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o; }
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) { o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o; }
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) { o << "{" << obj.first << ", " << obj.second << "}"; return o; }
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) { o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o; }
void print(void) { cout << endl; }
template <class Head> void print(Head&& head) { cout << head; print(); }
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) { cout << head << " "; print(forward<Tail>(tail)...); }
void YN(bool flg) { cout << ((flg) ? "YES" : "NO") << endl; }
void Yn(bool flg) { cout << ((flg) ? "Yes" : "No") << endl; }
void yn(bool flg) { cout << ((flg) ? "yes" : "no") << endl; }

template<class T> class Segment_Tree_Range_Maximum_Query {
public:
	int N;
	T ini;
	vector<T> node;

	Segment_Tree_Range_Maximum_Query(const vector<T> & ar, const T ini) : ini(ini) {
		for (N = 1; N < ar.size(); N *= 2);
		node.resize(2 * N - 1, ini);
		for (int i = 0; i<ar.size(); ++i) node[i + N - 1] = ar[i];
		for (int i = N - 2; i >= 0; --i) node[i] = max(node[2 * i + 1], node[2 * i + 2]);
	}

	void update(int idx, const T var) {
		idx += (N - 1);
		node[idx] = var;
		while (idx > 0) {
			idx = (idx - 1) / 2;
			node[idx] = max(node[2 * idx + 1], node[2 * idx + 2]);
		}
	}

	T getvar(const int a, const int b, int k = 0, int l = 0, int r = -1) {
		if (r < 0) r = N;
		if (r <= a || b <= l) return ini;
		if (a <= l && r <= b) return node[k];
		T vl = getvar(a, b, 2 * k + 1, l, (l + r) / 2);
		T vr = getvar(a, b, 2 * k + 2, (l + r) / 2, r);
		return max(vl, vr);
	}
};

int main() {
	int N; cin >> N;
	V<int> h(N); REP(i, N) cin >> h[i];
	V<ll> a(N); REP(i, N) cin >> a[i];
	V<ll> dp(N+1,0);
	Segment_Tree_Range_Maximum_Query<ll> Seg(dp,0LL);
	REP(i,N){
		dp[i] = Seg.getvar(0,h[i]) + a[i];
		Seg.update(h[i], dp[i]);
	}
	cout << *max_element(ALL(dp)) << endl;
	return 0;
}

Measured memory_bytes: 8320