#define _CRT_SECURE_NO_WARNINGS
#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii;
typedef long long ll; typedef vector<long long> vl; typedef pair<long long,long long> pll; typedef vector<pair<long long,long long> > vpll;
typedef vector<string> vs; typedef long double ld;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int N;
	scanf("%d", &N);
	vector<int> A(N);
	rep(i, N) scanf("%d", &A[i]);
	int M;
	scanf("%d", &M);
	vector<int> B(M);
	rep(i, M) scanf("%d", &B[i]);
	vector<int> sum(1 << N);
	rep(i, 1 << N) {
		int x = 0;
		rep(j, N) if(i >> j & 1)
			x += A[j];
		sum[i] = x;
	}
	vector<int> dp(1 << N, INF);
	dp[0] = 0;
	rep(i, M) {
		int b = B[i];
		for(int j = (1 << N)-1; j >= 0; -- j) {
			int x = dp[j];
			if(x == INF) continue;
			int rem = ((1 << N)-1) - j;
			for(int k = rem; ; (-- k) &= rem) {
				if(sum[k] <= b) amin(dp[j | k], x + 1);
				if(k == 0) break;
			}
		}
	}
	int ans = dp[(1 << N)-1];
	printf("%d\n", ans == INF ? -1 : ans);
	return 0;
}