#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<numeric>
#include<functional>
#include<complex>

using namespace std;
#define BET(a,b,c) ((a)<=(b)&&(b)<(c))
#define FOR(i,n) for(int i=0,i##_end=(int(n));i<i##_end;i++)
#define SZ(x) (int)(x.size())
#define ALL(x) (x).begin(),(x).end()
#define MP make_pair
#define FOR_EACH(it,v) for(__typeof(v.begin()) it=v.begin(),it_end=v.end() ; it != it_end ; it++)
typedef vector<int> VI;
typedef vector<VI> VVI;

int main()
{
    int N;    
    cin>>N;
    VI A(N);
    FOR(i,N) cin>>A[i];
    int M;
    cin>>M;
    VI B(M);
    FOR(i,M) cin>>B[i];
    sort(ALL(B), greater<int>());
    const int inf = 1<<28;
    VI dp(1<<N, inf);
    dp[0] = 0;
    for(auto v : B){
        VI pattern;
        FOR(i,1<<N){
            int sum = 0;
            FOR(j,N) if(i & (1<<j)){
                sum += A[j];
                if(sum > v) break;
            }
            if(sum <= v){
                pattern.push_back(i);
            }
        }
        for(int i=(1<<N)-1;i>=0;i--){
            for(auto p : pattern){
                if(i & p) continue;
                dp[i|p] = min(dp[i|p], dp[i] + 1);
            }
        }
    }
    
    cout<<(dp[(1<<N)-1] == inf ? -1 : dp[(1<<N)-1]) <<endl;
    return 0;
}