#include <bits/stdc++.h>

using namespace std;


const int dx[] = {1, 0, -1, 0}, dy[] = {0, -1, 0, 1};

int N,M;
vector<int> A,B;
int main(){
  cin >> N ;
  A.resize(N);
  for (int i = 0; i < N; i++){
    cin >> A[i];
  }
  cin >> M;
    B.resize(M);
  for (int i = 0; i < M; i++){
    cin >> B[i];
  }
  sort(A.begin(), A.end());
  sort(B.rbegin(), B.rend());
  int ans = 810;
  do{
    int pos = 0;
    for (int i = 0; i < M; i++){
      int rest = B[i];
      while (pos < N and rest >= A[pos]){
	rest -= A[pos];
	pos++;
      }
      if (pos >= N){
	ans = min(ans, (i + 1));
	break;
      }
    }
  }while(next_permutation(A.begin(), A.end()));
  
  if (ans >= 810){
    ans = -1;
  }
  cout << ans << endl;
}