package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
)

func out(x ...interface{}) {
	fmt.Println(x...)
}

var sc = bufio.NewScanner(os.Stdin)

func getInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func getInts(N int) []int {
	ret := make([]int, N)
	for i := 0; i < N; i++ {
		ret[i] = getInt()
	}
	return ret
}

func getString() string {
	sc.Scan()
	return sc.Text()
}

// min, max, asub, absなど基本関数
func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func asub(a, b int) int {
	if a > b {
		return a - b
	}
	return b - a
}

func abs(a int) int {
	if a >= 0 {
		return a
	}
	return -a
}

func lowerBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] >= x
	})
	return idx
}

func upperBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] > x
	})
	return idx
}

// NextPermutation generates the next permutation of the
// sortable collection x in lexical order.  It returns false
// if the permutations are exhausted.
//
// Knuth, Donald (2011), "Section 7.2.1.2: Generating All Permutations",
// The Art of Computer Programming, volume 4A.
// ※NextPermutationは辞書順で次を返す
func NextPermutation(x sort.Interface) bool {
	n := x.Len() - 1
	if n < 1 {
		return false
	}
	j := n - 1
	for ; !x.Less(j, j+1); j-- {
		if j == 0 {
			return false
		}
	}
	l := n
	for !x.Less(j, l) {
		l--
	}
	x.Swap(j, l)
	for k, l := j+1, n; k < l; {
		x.Swap(k, l)
		k++
		l--
	}
	return true
}

const inf = 100000

func main() {
	sc.Split(bufio.ScanWords)
	sc.Buffer([]byte{}, 1000000)
	N := getInt()
	a := getInts(N)
	M := getInt()
	b := getInts(M)
	sort.Ints(a)
	sort.Slice(b, func(i, j int) bool {
		return b[i] > b[j]
	})

	ans := inf
	for {
		c := make([]int, M)
		idx := 0
		for i := 0; i < N; i++ {
			for idx < M {
				if c[idx]+a[i] <= b[idx] {
					c[idx] += a[i]
					break
				} else {
					idx++
				}
			}
			if idx == M {
				break
			}
		}
		// out(c, idx, a)
		if idx < M {
			ans = min(ans, idx)
		}
		if NextPermutation(sort.IntSlice(a)) != true {
			break
		}
	}
	if ans == inf {
		out(-1)
	} else {
		out(ans + 1)
	}
}