/* -*- coding: utf-8 -*-
 *
 * 50.cc: No.50 おもちゃ箱 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 10;
const int NBITS = 1 << MAX_N;
const int MAX_M = 10;

const int INF = 1 << 30;

/* typedef */

typedef pair<int,int> pii;

/* global variables */

int as[MAX_N], bs[MAX_M];
pii dp[NBITS];

/* subroutines */

/* main */

int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> as[i];
  int nbits = 1 << n;

  int m;
  cin >> m;
  for (int i = 0; i < m; i++) cin >> bs[i];
  sort(bs, bs + m, greater<int>());

  for (int bits = 0; bits < nbits; bits++) dp[bits] = pii(INF, 0);
  dp[0] = pii(0, 0);

  for (int bits = 0; bits < nbits; bits++) {
    if (dp[bits].first >= INF) continue;
    
    for (int i = 0, bi = 1; i < n; i++, bi <<= 1)
      if (! (bits & bi)) {
	int vbits = bits | bi;
	int vdp0 = dp[bits].first, vdp1 = dp[bits].second;
	if (vdp1 + as[i] <= bs[vdp0]) vdp1 += as[i];
	else if (vdp0 < m - 1 && as[i] <= bs[vdp0 + 1]) vdp0++, vdp1 = as[i];
	else continue;

	pii vdp(vdp0, vdp1);
	if (dp[vbits] > vdp) {
	  dp[vbits] = vdp;
	  //printf(" dp[%d]=%d,%d\n", vbits, vdp0, vdp1);
	}
      }
  }
  //printf("dp:%d,%d\n", dp[nbits - 1].first, dp[nbits - 1].second);

  pii &dpn = dp[nbits - 1];
  if (dpn.first >= INF)
    puts("-1");
  else
    printf("%d\n", dpn.first + (dpn.second > 0 ? 1 : 0));

  return 0;
}