#include <bits/stdc++.h>
using namespace std;

#define INF_LL (int64)1e18
#define INF (int32)1e9
#define REP(i, n) for(int64 i = 0;i < (n);i++)
#define FOR(i, a, b) for(int64 i = (a);i < (b);i++)
#define all(x) x.begin(),x.end()
#define fs first
#define sc second

using int32 = int_fast32_t;
using uint32 = uint_fast32_t;
using int64 = int_fast64_t;
using uint64 = uint_fast64_t;
using PII = pair<int32, int32>;
using PLL = pair<int64, int64>;

const double eps = 1e-10;

template<typename A, typename B>inline void chmin(A &a, B b){if(a > b) a = b;}
template<typename A, typename B>inline void chmax(A &a, B b){if(a < b) a = b;}

const int64 mod = 1e9+7;

using Row = vector<int64>;
using Mat = vector<Row>;

template<class ValueMonoid, template<class...> class Container=::std::vector>
class SegTree{
public:
	using value_structure = ValueMonoid;
	using value_type = typename value_structure::value_type;
	using const_reference = const value_type &;
	using container_type = Container<value_type>;
	using size_type = typename container_type::size_type;

private:
	::std::vector<value_type> tree;
	size_type size_;

	static size_type getsize(const size_type x){
		size_type ret = 1;
		while(ret < x)
			ret <<= 1;
		return ret;
	}

	inline value_type calc(const value_type a, const value_type b){
		return value_structure::operation(a, b);
	}

	inline void calc_node(const size_type index){
		if(tree.size() <= (index << 1 | 1)) return;
		tree[index] = value_structure::operation(tree[index<<1], tree[index<<1 | 1]);
	}
public:
	SegTree() : size_(0), tree(){}
	SegTree(const size_type size)
			: size_(size), tree(size << 1, value_structure::identity()){}
	template<class InputIterator>
	SegTree(InputIterator first, InputIterator last)
			: size_(::std::distance(first, last)){
		tree = container_type(size_, value_structure::identity());
		tree.insert(tree.end(), first, last);
		for(size_type i = size_;i > 0;i--){
			calc_node(i);
		}
	}

	size_type size() const { return size_; }
	const_reference operator[](const size_type k) const {
		assert(k < size_);
		return tree[k+size_];
	}

	value_type query(size_type l, size_type r){
		assert(l <= r);
		assert(0 <= l && l < size_);
		assert(0 <= r && r <= size_);
		value_type retl = value_structure::identity(), retr = value_structure::identity();
		for(l += size_, r += size_; l < r ; l >>= 1, r >>= 1){
			if(l&1) retl = calc(retl, tree[l++]);
			if(r&1) retr = calc(tree[--r], retr);
		}
		return calc(retl, retr);
	}

	template<class F>
	void update(size_type index, const F& f){
		assert(0 <= index && index < size());
		index += size_;
		tree[index] = f(::std::move(tree[index]));
		while(index >>= 1)
			calc_node(index);
	}

	/*
	template<class F>
	size_type search(const F& f) const { // [0, result) is True and [0, result-1) is not.
		if(f(value_structure::identity()))
			return 0;
		if(!f(tree[1]))
			return size_+1;
		value_type acc = value_structure::identity();
		size_type i = 1;
		while(i < 
	}
	*/
};

class v_monoid{
public:
	using value_type = int64;
	static const value_type identity(){ return 0; }
	static const value_type initializer(){ return 0;}
	static value_type operation(const value_type& a, const value_type& b){
		return max(a, b);
	}
};

int32 N;
vector<int64> h;
vector<int64> a;

int main(void){
	cin >> N;
	h.resize(N);
	a.resize(N);
	REP(i, N) cin >> h[i];
	REP(i, N) cin >> a[i];
	SegTree<v_monoid> sg(N+1);
	REP(i, N){
		sg.update(h[i], [&](int64 x){return sg.query(0, h[i])+a[i];});
	}
	cout << sg.query(0, N+1) << endl;
}


Measured memory_bytes: 6528