using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using Enu = System.Linq.Enumerable;

class Program
{
    int ans = int.MaxValue;
    int[] A, B, use;

    void Solve()
    {
        int NA = reader.Int();
        A = reader.IntArray(NA).OrderByDescending(a => a).ToArray();
        int NB = reader.Int();
        B = reader.IntArray(NB);
        use = new int[NB];
        DFS(0, 0);
        if (ans == int.MaxValue) Console.WriteLine(-1);
        else Console.WriteLine(ans);
    }

    void DFS(int i, int count)
    {
        if (count >= ans) return;
        if (i == A.Length)
        {
            ans = Math.Min(ans, count);
            return;
        }
        for (int bi = 0; bi < B.Length; bi++)
            if (A[i] + use[bi] <= B[bi])
            {
                use[bi] += A[i];
                DFS(i + 1, count + (use[bi] == A[i] ? 1 : 0));
                use[bi] -= A[i];
            }
    }




    Reader reader = new Reader(Console.In);
    static void Main() { new Program().Solve(); }
}

class Reader
{
    private readonly TextReader reader;
    private readonly char[] separator = { ' ' };
    private readonly StringSplitOptions removeOp = StringSplitOptions.RemoveEmptyEntries;
    private string[] A = new string[0];
    private int i;

    public Reader(TextReader r) { reader = r; }
    public Reader(string file) { reader = new StreamReader(file); }
    public bool HasNext() { return Enqueue(); }
    public string String() { return Dequeue(); }
    public int Int() { return int.Parse(Dequeue()); }
    public long Long() { return long.Parse(Dequeue()); }
    public double Double() { return double.Parse(Dequeue()); }
    public int[] IntLine() { var s = Line(); return s == "" ? new int[0] : Array.ConvertAll(Split(s), int.Parse); }
    public int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public int[][] IntGrid(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public string Line() { return reader.ReadLine().Trim(); }
    private string[] Split(string s) { return s.Split(separator, removeOp); }
    private bool Enqueue()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return Enqueue();
        A = Split(line);
        i = 0;
        return true;
    }
    private string Dequeue() { Enqueue(); return A[i++]; }
}