using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Text;
using System.Linq;

using E = System.Linq.Enumerable;

internal partial class Solver {
    public void Run() {
        var n = ni();
        var h = ni(n);
        var a = ni(n);
        for (int i = 0; i < n; i++) {
            h[i]--;
        }
        var dp = new long[n];
        var rmq = new RMQSegmentTree();
        rmq.Build(n, i => 0);

        for (int i = 0; i < n; i++) {
            if (h[i] > 0) {
                dp[i] = rmq.Query(0, h[i]);
            }
            dp[i] += a[i];
            rmq.Update(h[i], dp[i]);
        }
        cout.WriteLine(dp.Max());
    }
}

public abstract class SegmentTree<TMonoid> where TMonoid : struct {
    protected int N { get; private set; }
    protected TMonoid?[] node;
    protected static int Left(int p) { return p * 2 + 1; }
    protected static int Right(int p) { return p * 2 + 2; }

    public SegmentTree() { }

    public void Build(IList<TMonoid> array) {
        Build(array.Count, i => array[i]);
    }

    public virtual void Build(int _n, Func<int, TMonoid> create) {
        N = 1;
        while (N < _n) {
            N *= 2;
        }

        node = new TMonoid?[2 * N];

        for (int i = 0; i < _n; i++) {
            node[i + N - 1] = create(i);
        }

        for (int i = N - 2; i >= 0; i--) {
            node[i] = Merge(node[Left(i)], node[Right(i)]);
        }
    }

    protected TMonoid? Merge(TMonoid? left, TMonoid? right) {
        if (left != null && right != null) {
            return Merge(left.Value, right.Value);
        }

        if (left == null) {
            return right;
        }

        if (right == null) {
            return left;
        }

        return null;
    }

    protected abstract TMonoid Merge(TMonoid left, TMonoid right);

    public void Update(int index, TMonoid val) {
        int p = index + N - 1;
        node[p] = val;
        while (p > 0) {
            p = (p - 1) / 2;
            node[p] = Merge(node[Left(p)], node[Right(p)]);
        }
    }

    protected virtual TMonoid? Query(int begin, int end, int k, int l, int r) {
        if (r <= begin || end <= l) {
            return null;
        }

        if (begin <= l && r <= end) {
            return node[k];
        }

        int mid = (l + r) / 2;
        return Merge(
            Query(begin, end, Left(k), l, mid),
            Query(begin, end, Right(k), mid, r)
        );
    }

    public TMonoid Query(int begin, int end) {
        return Query(begin, end, 0, 0, N).Value;
    }
};

public class RMQSegmentTree : SegmentTree<long> {
    protected override long Merge(long x, long y) {
        return Math.Max(x, y);
    }
}
// PREWRITEN CODE BEGINS FROM HERE
internal partial class Solver : Scanner {
    public static void Main(string[] args) {
#if LOCAL
        byte[] inputBuffer = new byte[1000000];
        var inputStream = Console.OpenStandardInput(inputBuffer.Length);
        using (var reader = new StreamReader(inputStream, Console.InputEncoding, false, inputBuffer.Length)) {
            Console.SetIn(reader);
            new Solver(Console.In, Console.Out).Run();
        }
#else
        Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        new Solver(Console.In, Console.Out).Run();
        Console.Out.Flush();
#endif
    }

#pragma warning disable IDE0052
    private readonly TextReader cin;
    private readonly TextWriter cout;
#pragma warning restore IDE0052

    public Solver(TextReader reader, TextWriter writer)
        : base(reader) {
        cin = reader;
        cout = writer;
    }
    public Solver(string input, TextWriter writer)
        : this(new StringReader(input), writer) {
    }

#pragma warning disable IDE1006
#pragma warning disable IDE0051
    private int ni() { return NextInt(); }
    private int[] ni(int n) { return NextIntArray(n); }
    private long nl() { return NextLong(); }
    private long[] nl(int n) { return NextLongArray(n); }
    private double nd() { return NextDouble(); }
    private double[] nd(int n) { return NextDoubleArray(n); }
    private string ns() { return Next(); }
    private string[] ns(int n) { return NextArray(n); }
#pragma warning restore IDE1006
#pragma warning restore IDE0051
}

internal static class LinqPadExtension {
    [Conditional("DEBUG")]
    public static void Dump<T>(this T obj) {
#if DEBUG
        LINQPad.Extensions.Dump(obj);
#endif
    }
}

public class Scanner {
    private readonly TextReader Reader;
    private readonly CultureInfo ci = CultureInfo.InvariantCulture;

    private readonly char[] buffer = new char[2 * 1024];
    private int cursor = 0, length = 0;
    private string Token;
    private readonly StringBuilder sb = new StringBuilder(1024);

    public Scanner()
        : this(Console.In) {
    }

    public Scanner(TextReader reader) {
        Reader = reader;
    }

    public int NextInt() { return (int)NextLong(); }
    public long NextLong() {
        var s = Next();
        long r = 0;
        int i = 0;
        bool negative = false;
        if (s[i] == '-') {
            negative = true;
            i++;
        }
        for (; i < s.Length; i++) {
            r = r * 10 + (s[i] - '0');
#if DEBUG
            if (!char.IsDigit(s[i])) throw new FormatException();
#endif
        }
        return negative ? -r : r;
    }
    public double NextDouble() { return double.Parse(Next(), ci); }
    public string[] NextArray(int size) {
        string[] array = new string[size];
        for (int i = 0; i < size; i++) {
            array[i] = Next();
        }

        return array;
    }
    public int[] NextIntArray(int size) {
        int[] array = new int[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextInt();
        }

        return array;
    }

    public long[] NextLongArray(int size) {
        long[] array = new long[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextLong();
        }

        return array;
    }

    public double[] NextDoubleArray(int size) {
        double[] array = new double[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextDouble();
        }

        return array;
    }

    public string Next() {
        if (Token == null) {
            if (!StockToken()) {
                throw new InvalidOperationException();
            }
        }
        var token = Token;
        Token = null;
        return token;
    }

    public bool HasNext() {
        if (Token != null) {
            return true;
        }

        return StockToken();
    }

    private bool StockToken() {
        while (true) {
            sb.Clear();
            while (true) {
                if (cursor >= length) {
                    cursor = 0;
                    if ((length = Reader.Read(buffer, 0, buffer.Length)) <= 0) {
                        break;
                    }
                }
                var c = buffer[cursor++];
                if (33 <= c && c <= 126) {
                    sb.Append(c);
                } else {
                    if (sb.Length > 0) break;
                }
            }

            if (sb.Length > 0) {
                Token = sb.ToString();
                return true;
            }

            return false;
        }
    }
}

Measured memory_bytes: 25940