#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;
const ll inf = 1e9;
const ll mod = 1e9 + 7;

int N, A[10], M, B[10];
int lim;
int used[10];

int calc(int k) {
	if (k == N) {
		int res = 0;
		rep (i, lim) res += used[i] > 0;
		return res;
	}

	int res = inf;
	rep (i, lim) {
		if (B[i] >= A[k]) {
			B[i] -= A[k];
			used[i]++;
			res = min(res, calc(k + 1));
			used[i]--;
			B[i] += A[k];
		}
	}
	return res;
}

int main() {
	cin >> N;
	rep (i, N) cin >> A[i];
	cin >> M;
	rep (i, M) cin >> B[i];
	sort(B, B + M);
	reverse(B, B + M);

	int ans = inf;
	rep2 (i, 1, M + 1) {
		lim = i;	
		int c = calc(0);
		if (c != inf) {
			ans = i;
			break;		
		}
	}

	if (ans == inf) ans = -1;
	cout << ans << endl;

	return 0;
}