import java.util.*;

public class Main {
    static HashSet<String> set = new HashSet<>();
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] toys = new int[n];
		for (int i = 0; i < n; i++) {
		    toys[i] = sc.nextInt();
		}
		Arrays.sort(toys);
		int m = sc.nextInt();
		int[] boxes = new int[m];
		for (int i = 0; i < m; i++) {
		    boxes[i] = sc.nextInt();
		}
		Arrays.sort(boxes);
		int idx = m;
		for (int i = n - 1; i >= 0; i--) {
		    if (toys[i] == 0) {
		        continue;
		    }
		    idx--;
		    if (idx < 0 || boxes[idx] < toys[i]) {
		        System.out.println(-1);
		        return;
		    }
		    int remain = boxes[idx] - toys[i];
		    int left = i - 1;
		    while (remain > 0 && left >= 0) {
		        if (remain >= toys[left]) {
		            remain -= toys[left];
		            toys[left] = 0;
		        }
		        left--;
		    }
		}
		System.out.println(m - idx);
   }
}