#include <bits/stdc++.h>
using namespace std;

int main(void) {
	int N;
	cin >> N;
	vector<int> A(N);
	for(int i = 0; i < N; ++i) cin >> A[i];
	int M;
	cin >> M;
	vector<int> B(M);
	for(int i = 0; i < M; ++i) cin >> B[i];
	sort(B.rbegin(), B.rend());
	
	sort(A.begin(), A.end());
	int ans = 1e9;
	do {
		int cnt = 0, nv = 0;
		for(int i = 0; i < N; ++i) {
			if(cnt >= M) {
				cnt = 1e9;
				break;
			}
			if(nv + A[i] > B[cnt]) ++cnt, nv = 0, --i;
			else nv += A[i];
		}
		
		ans = min(ans, cnt + 1);
	} while(next_permutation(A.begin(), A.end()));
	
	cout << (ans > 100 ? -1 : ans) << "\n";
	
	return 0;
}