#include<bits/stdc++.h>
using namespace std;

typedef long long int ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pair<int, int> > vii;
#define rrep(i, m, n) for(int (i)=(m); (i)<(n);  (i)++)
#define erep(i, m, n) for(int (i)=(m); (i)<=(n); (i)++)
#define  rep(i, n)    for(int (i)=0; (i)<(n);  (i)++)
#define  rev(i, n)    for(int (i)=(n)-1; (i)>=0; (i)--)
#define vrep(i, c)    for(__typeof((c).begin())i=(c).begin(); i!=(c).end(); i++)
#define  ALL(v)       (v).begin(), (v).end()
#define mp            make_pair
#define pb            push_back
template<class T1, class T2> inline void minup(T1& m, T2 x){ if(m>x) m=static_cast<T2>(x); }
template<class T1, class T2> inline void maxup(T1& m, T2 x){ if(m<x) m=static_cast<T2>(x); }

#define INF 1000000000
#define MOD 1000000007
#define EPS 1E-12

const int MAX_N = 10;
const int MAX_M = 10;
int n, m;
int a[MAX_N];
int b[MAX_M];
int dp[MAX_M+1][1<<(MAX_N+1)];

int main()
{
  cin >> n;  rep(i, n) cin >> a[i];
  cin >> m;  rep(i, m) cin >> b[i];

  sort(b, b + m, greater<int>());

  rep(i, m+1) rep(j, 1<<n) dp[i][j] = INF;

  dp[0][0] = 0;
  rep(v, m) rep(S, 1<<n){
    minup(dp[v + 1][S], dp[v][S]);

    rep(T, 1<<n) if(!(S & T)){
      int w = 0;
      rep(i, n) if(T & 1 << i) w += a[i];
      if(w > b[v]) continue;
      minup(dp[v + 1][S | T], dp[v][S] + 1);
    }
  }

  cout << (dp[m][(1<<n)-1] >= INF ? -1 : dp[m][(1<<n)-1]) << endl;

  return 0;
}