package main

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

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 := getInts(N)
	b := getInts(N)
	ma := 0
	idx := 0
	for i := 0; i < N; i++ {
		if ma < b[i]-a[i] {
			ma = max(ma, b[i]-a[i])
			idx = i
		}
	}

	same := 0
	m := make(map[int]int)
	for i := 0; i < N; i++ {
		if i == idx {
			a[i] += ma
		} else {
			a[i] -= ma
		}
		if a[i] == b[i] {
			same++
		} else {
			m[b[i]-a[i]]++
		}
	}

	if len(m) == 0 {
		out(ma)
		return
	}

	if same == 2 && len(m) == 1 {
		x := 0
		for i := range m {
			x = i
		}
		if x < 0 {
			out(ma - x)
			return
		}
	}
	// out(a, same, m)
	out(-1)
}