import java.util.*;
import java.io.*;
import java.math.BigInteger;

public class Main {
	static PrintWriter out;
	static StringBuilder sb;
	static final double EPS = 1e-9;
	static long mod = (int) 1e9 + 7;
	static int inf = (int) 1e9 + 2;
	static long[] fac;
	static int[] si;
	static ArrayList<Integer> primes;
	static ArrayList<Integer>[] ad;
	static ArrayList<pair>[] d;
	static edge[] ed;
	static boolean[] vis;
	static int[] l, ch;
	static int[] occ;
	static Queue<Integer>[] can;
	static String s;
	static long [][] memo;

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		int n=sc.nextInt();
		int []a=new int [n];
		long []ans=new long [n];
		FenwickTree v=new FenwickTree(n);
		for(int i=0;i<n;i++)
			a[i]=sc.nextInt();
		for(int i=0;i<n;i++)
			ans[i]=sc.nextInt();
		for(int i=n-1;i>=0;i--) {
			long k=v.rsq(a[i]);
		//	System.out.println(Arrays.toString(v.ft)+" "+k+" "+(i+1));
			v.point_update(a[i], k+ans[i]);
		}
		long o=0;
		for(int i=0;i<=n;i++)
			o=Math.max(o, v.ft[i]);
	//	System.out.println(Arrays.toString(v.ft));
		out.print(o);
		out.flush();
	}
	static public class FenwickTree { // one-based DS

		int n;
		long[] ft;
		
		FenwickTree(int size) { n = size; ft = new long[n+1]; }
		
		long rsq(int b) //O(log n)
		{
			long max = 0;
			while(b <= n) { max = Math.max(max, ft[b]); b += b & -b;
			}		//min?
			return max;
		}
		void point_update(int k, long val)	//O(log n), update = increment
		{
			while(k >0) { ft[k] =Math.max(ft[k], val); k -= k & -k; 
		}		//min?
		}
	}
	static long inver(long x, long kk) {
		int a = (int) x;
		long e = (kk - 2);
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1) {
				// System.out.println(res*a);
				res = (int) ((1l * res * a) % kk);
			}
			a = (int) ((1l * a * a) % kk);
			e >>= 1;
		}
		// out.println(res+" "+x);
		return res % kk;
	}

	static TreeSet<Integer> trr;

	static class qu implements Comparable<qu> {
		int i, j;

		qu(int a, int s) {
			i = a;
			j = s;
		}

		public String toString() {
			return i + " " + j;
		}

		public int compareTo(qu o) {
			if (i == o.i)
				return j - o.j;
			return i - o.i;
		}
	}

	static class pair {
		int to;
		int number;

		pair(int t, int n) {
			number = n;
			to = t;
		}

		public String toString() {
			return to + " " + number;
		}
	}

	static double modPow(double a, int e)

	{
		double res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a);
			a = (a * a);
			e >>= 1;
		}
		return res;
	}

	static boolean[] in;

	/*
	 * static void mst() { Arrays.sort(ed); UnionFind uf=new UnionFind(n); for(int
	 * i=0;i<m;i++) { edge w=ed[i]; if(!uf.union(w.from, w.to)) continue;
	 * in[i]=true; } }
	 */
	static class edge implements Comparable<edge> {
		int from;
		int to;
		int number;

		edge(int f, int t, int n) {
			from = f;
			to = t;
			number = n;
		}

		public String toString() {
			return from + " " + to + " " + number;
		}

		public int compareTo(edge f) {
			return number - f.number;
		}
	}

	static class seg implements Comparable<seg> {
		int a;
		int b;

		seg(int s, int e) {
			a = s;
			b = e;
		}

		public String toString() {
			return a + " " + b;
		}

		public int compareTo(seg o) {
			// if(a==o.a)
			return o.b - b;
			// return
		}
	}

	static long power(int i) {
		// if(i==0)
		// return 1;
		long a = 1;
		for (int k = 0; k < i; k++)
			a *= i;
		return a;
	}

	static void seive(int N) {
		si = new int[N];
		primes = new ArrayList<>();
		si[1] = 1;
		for (int i = 2; i < N; i++) {
			if (si[i] == 0) {
				si[i] = i;
				primes.add(i);
			}
			for (int j = 0; j < primes.size() && primes.get(j) <= si[i] && (i * primes.get(j)) < N; j++)
				si[primes.get(j) * i] = primes.get(j);

		}
	}

	static long fac(int n) {
		if (n == 0)
			return fac[n] = 1;
		if (n == 1)
			return fac[n] = 1;
		long ans = 1;
		for (int i = 1; i <= n; i++)
			fac[i] = ans = (i % mod * ans % mod) % mod;
		return ans % mod;
	}

	static long gcd(long a, long b) {

		if (b == 0)
			return a;
		return gcd(b, a % b);
	}

	static class unionfind {
		int[] p;
		int[] size;

		unionfind(int n) {
			p = new int[n];
			size = new int[n];

			for (int i = 0; i < n; i++) {
				p[i] = i;
			}
			Arrays.fill(size, 1);
		}

		int findSet(int v) {
			if (v == p[v])
				return v;
			return p[v] = findSet(p[v]);
		}

		boolean sameSet(int a, int b) {
			a = findSet(a);
			b = findSet(b);
			if (a == b)
				return true;
			return false;
		}

		int max() {
			int max = 0;
			for (int i = 0; i < size.length; i++)
				if (size[i] > max)
					max = size[i];
			return max;
		}

		boolean combine(int a, int b) {
			a = findSet(a);
			b = findSet(b);
			if (a == b)
				return true;
			if (size[a] > size[b]) {
				p[b] = a;
				size[a] += size[b];

			} else {
				p[a] = b;
				size[b] += size[a];
			}
			return false;
		}
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	}
}

Measured memory_bytes: 68460