#include <iostream>
#include <algorithm>
#define INF (2 << 28)
using namespace std;

int n, m;
int a[11], b[11], dp[1<<10][1<<10];

int rec(int toy, int used){

  //cout << toy << " " << used << endl;
  if(toy == 0) return __builtin_popcount(used);
  if(dp[toy][used]) return dp[toy][used];
  
  int ret = INF;
  for(int i = 0; i < n; i++){
    for(int j = 0; j < m; j++){
      if(a[i] <= b[j] && toy >> i & 1){
	b[j] -= a[i];
	ret = min(ret, rec(~(1 << i) & toy, used | (1 << j)));
	b[j] += a[i];
      }
    }
  }

  return dp[toy][used] = ret;
}
    
int main(){
  
  cin >> n;
  for(int i = 0; i < n; i++) cin >> a[i];
  cin >> m;
  for(int i = 0; i < m; i++) cin >> b[i];
  
  int d = rec((1<<n)-1, 0);
  if(d == INF) cout << -1 << endl;
  else cout << d << endl;
}