#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
#include <sstream>
 
#include <algorithm>
#include <cmath>
 
#include <string>
//#include <array>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
 
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	
	int N,M;
	vector<int> A,B;

	cin>>N;
	A.reserve(N);
	int temp;
	rep(i,N){
		cin>>temp;
		A.push_back(temp);
	}

	cin>>M;
	B.reserve(M);
	rep(i,M){
		cin>>temp;
		B.push_back(temp);
	}
	sort(A.begin(), A.end(), greater<int>() );
	sort(B.begin(), B.end(), greater<int>() );
	vector<int>::iterator itA,itB,Abegin,Aend,Bbegin,Bend;
	int ans = M+1;
	int tans,nokori;
	Abegin = A.begin();
	Aend = A.end();
	Bbegin = B.begin();
	Bend = B.end();
	do{
		itA = Abegin;
		tans = 0;
		for(itB = Bbegin; itB!=Bend && itA!=Aend; ++itB){
			++tans;
			nokori = *itB;
			while( itA!=Aend && nokori > 0){
				if( nokori >= (*itA) ){
					nokori -= *itA;
					++itA;
				}else{
					nokori -= *itA;
				}
			}
		}
		if( itA == Aend ){
			ans = min(ans,tans);
		}
	}while( prev_permutation(Abegin,Aend) );
	if( ans > M ){
		P(-1);
	}else{
		P(ans);
	}
	return 0;
}