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



class Myon
{
    public Myon() { }
    public static int Main()
    {
        new Myon().calc();
        return 0;
    }

    Scanner cin;

    int N;


    long[,] dp;
    int[] predp;
    List<int>[] es;

    long mod = 1000000007;


    void calc()
    {
        cin = new Scanner();
        int N = cin.nextInt();
        int[] h = cin.ArrayInt(N);
        long[] a = cin.ArrayLong(N);

        BIT dp = new BIT(N + 5);
        for (int i = 0; i < N; i++)
        {
            dp.bitUpdate(h[i], a[i] + dp.bitCal(h[i] - 1));
        }

        Console.WriteLine(dp.bitCal(N + 2));
    }

    class BIT
    {
        int bitA;
        long[] bit;
        const long INF = long.MaxValue - 10;

        public BIT(int maxa)
        {
            bitA = maxa;
            bit = new long[bitA + 1];
            for (int i = 0; i < bitA; i++)
            {
                bit[i] = 0;
            }
        }

        public void bitErase(int a)
        {
            for (int i = a; i <= bitA; i += i & -i)
            {
                bit[i] = -INF;
            }
        }
        public void bitUpdate(int a, long val)
        {
            for (int i = a; i <= bitA; i += i & -i)
            {
                bit[i] = Math.Max(bit[i], val);
            }
        }
        public long bitCal(int a)
        {
            long ret = 0;
            for (int i = a; i > 0; i &= i - 1)
            {
                ret = Math.Max(ret, bit[i]);
            }
            return ret;
        }
    }





}


class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        if (s.Length == 0) return next();
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }
    public int[] ArrayInt(int N, int add = 0)
    {
        int[] Array = new int[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextInt() + add;
        }
        return Array;
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public long[] ArrayLong(int N, long add = 0)
    {
        long[] Array = new long[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextLong() + add;
        }
        return Array;
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }


    public double[] ArrayDouble(int N, double add = 0)
    {
        double[] Array = new double[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextDouble() + add;
        }
        return Array;
    }
}

class XRand
{
    uint x, y, z, w;


    public XRand()
    {
        init();
    }

    public XRand(uint s)
    {
        init();
        init_xor128(s);
    }

    void init()
    {
        x = 314159265; y = 358979323; z = 846264338; w = 327950288;

    }

    public void init_xor128(uint s)
    {
        z ^= s;
        z ^= z >> 21; z ^= z << 35; z ^= z >> 4;
        z *= 736338717;
    }

    uint next()
    {
        uint t = x ^ x << 11; x = y; y = z; z = w; return w = w ^ w >> 19 ^ t ^ t >> 8;
    }

    public long nextLong(long m)
    {
        return (long)((((ulong)next() << 32) + next()) % (ulong)m);
    }

    public int nextInt(int m)
    {
        return (int)(next() % m);
    }

    public int nextIntP(int a)
    {
        return (int)Math.Pow(a, nextDouble());
    }

    public int nextInt(int min, int max)
    {
        return min + nextInt(max - min + 1);
    }


    public double nextDouble()
    {
        return (double)next() / uint.MaxValue;
    }

    public double nextDoubleP(double a)
    {
        return Math.Pow(a, nextDouble());
    }
}



Measured memory_bytes: 43792