#include <iostream>
#include <algorithm>
using namespace std;

#define FOR(i,s,e) for(int i = (s);i <= (e);i++)

int N;
int A[10];

int M;
int B[10];


int main()
{
	cin >> N;
	FOR(i,0,N - 1)
	{
		cin >> A[i];
	}
	cin >> M;
	FOR(i,0,M - 1)
	{
		cin >> B[i];
	}


	sort(B,B + M);
	reverse(B,B + M);
	sort(A,A+N);
	int result = 11;
	do
	{
		int box[M];
		FOR(i,0,M - 1) box[i] = B[i];
		int cou = 0;
		bool success = true;
		FOR(i,0,N -1)
		{
			bool update = false;
			FOR(j,0,M - 1)
			{
				if(box[j] - A[i] >= 0)
				{
					box[j] -= A[i];
					cou = max(cou,j + 1);
					update = true;

					break;
				}
			}
			if(update == false)
			{
				success = false;
				break;
			}
		}
		if(success)
		{
			result = min(result,cou);
		}
	}while(next_permutation(A,A + N));
if(result == 11) result = -1;
	cout << result << endl;
	return 0;
}