#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
    int n;
    while (cin>>n) {
        vector<int> a(n); for(int& v: a) cin>>v;
        sort(begin(a), end(a));

        int m; cin>>m;
        vector<int> b(m); for(int& v: b) cin>>v;
        sort(b.rbegin(), b.rend());

        int res=m;
        auto t=b;
        do {
            b=t;
            int k=0;
            for(int i=0;i<n;++i) {
                while (k<m and b[k]<a[i]) ++k;
                if (k==m) break;
                b[k]-=a[i];
            }
            res=min(res, k);
        } while (next_permutation(begin(a), end(a)));
        cout<<(res<m ? res+1 : -1)<<endl;
    }
}