using System;
using System.Collections.Generic;
using System.Collections;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using static System.Math;
using System.Numerics;
//using nint=System.Int32;
static class Program{
	const int mod=(int)1e9+7;
	const double eps=1e-11;
	static void Main(){
		Sc sc=new Sc();
		var n=sc.I;
		var a=sc.Ia;
		var m=sc.I;
		var b=sc.Ia;
		int f=1<<n;
		var ba=new bool[m][];
		var da=new bool[m][];
		for(int i = 0;i<m;i++) {
			ba[i]=new bool[f];
			da[i]=new bool[f];
		}
		for(int i = 0;i<f;i++) {
			int p=0;
			for(int j = 0;1<<j<=i;j++) {
				if((i&(1<<j))!=0){p+=a[j];}
			}
			for(int j = 0;j<m;j++) {
				if(b[j]>=p){ba[j][i]=true;}
			}
		}
		bool bo=false;
		int ans=m+1;
		Fu(0,f-1,0);

		void Fu(int c,int d,int p) {
			if(d==0){
				bo=true;
				ans=Min(ans,p);
				return;
			}
			if(c==m||p+1>=ans||da[c][d]){return;}
			for(int i=d;i>0;i=(i-1)&d){
				if(ba[c][i]){
					Fu(c+1,d-i,p+1);
				}
			}
			Fu(c+1,d,p);
			da[c][d]=true;
		}
		Console.WriteLine("{0}",bo?ans:-1);
	}
}

public class Sc{
	public int I{get{return int.Parse(Console.ReadLine());}}
	public long L{get{return long.Parse(Console.ReadLine());}}
	public double D{get{return double.Parse(Console.ReadLine());}}
	public string S{get{return Console.ReadLine();}}
	public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}}
	public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}}
	public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}}
	public string[] Sa{get{return Console.ReadLine().Split();}}
	public object[] Oa{get{return Console.ReadLine().Split();}}
	public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}}
	public int[] Ia3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),int.Parse);}
	public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}}
	public long[] La3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),long.Parse);}
	public double[] Da2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),double.Parse);}}
	public double[] Da3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),double.Parse);}
	public T[] Arr<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Console.ReadLine().Split());}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Console.ReadLine().Split());}return a;}
}