import java.util.*;
import java.io.*;

public class Main {
    static int n;
    static int[] toys;
    static int m;
    static int[] boxes;
    static final int MAX = 20;
    static int[][][] dp;
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        n = Integer.parseInt(br.readLine());
        toys = new int[n];
        String[] first = br.readLine().split(" ", n);
        for (int i = 0; i < n; i++) {
            toys[i] = Integer.parseInt(first[i]);
        }
        m = Integer.parseInt(br.readLine());
        boxes = new int[m];
        String[] second = br.readLine().split(" ", m);
        for (int i = 0; i < m; i++) {
            boxes[i] = Integer.parseInt(second[i]);
        }
        Arrays.sort(boxes);
        dp = new int[m][MAX + 1][1 << n];
        int value = dfw(m - 1, boxes[m - 1], (1 << n) - 1) + 1;
        if (value > m) {
            System.out.println(-1);
        } else {
            System.out.println(value);
        }
    }
    
    static int dfw(int b, int size, int key) {
        if (b < 0) {
            return Integer.MAX_VALUE / 10;
        }
        if (key == 0) {
            return 0;
        }
        if (dp[b][size][key] != 0) {
            return dp[b][size][key];
        }
        int min = Integer.MAX_VALUE;
        int count = 0;
        for (int i = 0; i < n; i++) {
            int x = 1 << i;
            if ((x & key) == 0) {
                continue;
            }
            if (toys[i] > size) {
                continue;
            }
            count++;
            min = Math.min(min, dfw(b, size - toys[i], key ^ x));
        }
        if (count == 0) {
            if (b < 1) {
                return Integer.MAX_VALUE / 10;
            }
            min = dfw(b - 1, boxes[b - 1], key) + 1;
        }
        dp[b][size][key] = min;
        return min;
    }
}