package main

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

var sc = bufio.NewScanner(os.Stdin)
var wr = bufio.NewWriter(os.Stdout)

func out(x ...interface{}) {
	fmt.Fprintln(wr, x...)
}

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

func getF() float64 {
	sc.Scan()
	i, e := strconv.ParseFloat(sc.Text(), 64)
	if e != nil {
		panic(e)
	}
	return i
}

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

func getS() 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
}

func main() {
	defer wr.Flush()
	sc.Split(bufio.ScanWords)
	sc.Buffer([]byte{}, 1000000)
	// this template is new version.
	// use getI(), getS(), getInts(), getF()
	N := getI()
	a := make([]string, N)
	for i := 0; i < N; i++ {
		a[i] = getS()
	}
	M := getI()
	b := make([]string, M)
	for i := 0; i < M; i++ {
		b[i] = getS()
	}

	if M < N {
		N, M = M, N
		a, b = b, a
	}

	x := make([]int, N)
	for i := 0; i < N; i++ {
		x[i] = i
	}
	cnt := 0
	ans := ""
	for {
		s := ""
		for i := 0; i < N; i++ {
			s += a[x[i]]
		}
		ok := true
		for i := 0; i < M; i++ {
			if !strings.Contains(s, b[i]) {
				ok = false
			}
		}
		if ok {
			cnt++
			ans = s
			if cnt == 2 {
				out(-1)
				return
			}
		}
		if NextPermutation(sort.IntSlice(x)) == false {
			break
		}
	}
	if cnt == 1 {
		out(ans)
		return
	}
	out(-1)
}

// 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
}