#include <bits/stdc++.h>

using namespace std;

#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = 1e18;
const ll MOD = 1000000007;
//const ll MOD = 998244353;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { 1,0, -1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
//#define mp make_pair



class SegmentTree {
public:
	const ll MAX_N = 1 << 20;
	int n;
	vl dat;
	vl a;

	SegmentTree(int _n, vl _a) :n(_n), a(_a) { dat.resize(2 * MAX_N - 1); }
	SegmentTree() { dat.resize(2 * MAX_N - 1); }

	void init(int k, int l, int r) {
		if (r - l == 1) {
			dat[k] = a[l];
		}
		else {
			int lch = 2 * k + 1, rch = 2 * k + 2;
			init(lch, l, (l + r) / 2);
			init(rch, (l + r) / 2, r);
			dat[k] = max(dat[lch], dat[rch]);
		}
	}


	//k番目の値をaに変更
	void update(int k, ll a, int v, int l, int r) {
		if (r - l == 1) {
			dat[v] = a;
		}
		else {
			if (k < (l + r) / 2)
				update(k, a, 2 * v + 1, l, (l + r) / 2);
			else {
				update(k, a, 2 * v + 2, (l + r) / 2, r);
			}
			dat[v] = max(dat[v * 2 + 1], dat[v * 2 + 2]);
		}
	}

	//[a,b)の最小値を求める
	//後ろのほうの引数は計算の簡単のための引数
	//kは接点の番号,l,rはその接点が[l,r)に対応していることを表す
	//従って、外からはquery(a,b,0,0,n)としてよぶ
	ll query(int a, int b, int k, int l, int r) {
		if (r <= a || b <= l) {
			return -INF;
		}
		if (a <= l && r <= b) {
			return dat[k];
		}
		else {
			ll ul = query(a, b, k * 2 + 1, l, (l + r) / 2);
			ll ur = query(a, b, k * 2 + 2, (l + r) / 2, r);
			return max(ul, ur);
		}
	}

};


int main() {
  fio();
  int n;
  cin >> n;
  vl h(n), a(n);
  rep (i, n) {
    cin >> h[i];
  }
  rep (i, n) {
    cin >> a[i];
  }
  vl on(n + 1, -INF);
  on[0] = 0;
  SegmentTree seg(n + 1, on);
  rep (i, n) {
    int idx = h[i];
    ll now = seg.query(idx, idx + 1, 0, 0, seg.n);
    ll nex = seg.query(0, idx, 0, 0, seg.n) + a[i];
    if (now < nex) {
      seg.update(idx, nex, 0, 0, seg.n);
    }
  }
  cout << seg.query(0, seg.n, 0, 0, seg.n) << endl;
}


Measured memory_bytes: 24448