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

int main() {
  int N;
  cin >> N;

  vector<int> A(N);
  for (int i = 0; i < N; ++i) {
    cin >> A[i];
  }

  int M;
  cin >> M;

  vector<int> B(M);
  for (int i = 0; i < M; ++i) {
    cin >> B[i];
  }

  sort(B.begin(), B.end(), greater<int>());

  int res = 0x3f3f3f3f;
  sort(A.begin(), A.end());
  do {
    int c = 0x3f3f3f3f;
    for (int i = 0, j = 0; i < M; ++i) {
      int s = 0;
      while (j < N && s + A[j] <= B[i]) s += A[j++];
      if (j == N) {
        c = i + 1;
        break;
      }
    }
    res = min(res, c);
  } while (next_permutation(A.begin(), A.end()));

  if (res == 0x3f3f3f3f) res = -1;
  cout << res << endl;

  return 0;
}