n = int(input())
a = [int(i) for i in input().split()]
b = [int(i) for i in input().split()]

li = [0]*n
ans = 0
parity = (b[0]-a[0])%2
for i in range(n):
    li[i] = b[i]-a[i]
    if li[i] % 2 != parity:
        print(-1)
        exit()

li.sort(reverse=True)
f = True
for i in range(n):
    if li[i] != 0:
        f = False
        break
if f == True:
    print(0)
    exit()

if li[n-1] > 0:
    print(-1)
    exit()

ttl = -li[n-1]
itr = 10**7
hiku = 0
tasu = 0

for i in range(n):
    tmp = (ttl+li[i])//2
    tasu += tmp
    hiku += ttl-tmp
#print(tasu,hiku,"ttl?")
if tasu*(n-1) == hiku:
    print(ttl)
    exit()

for i in range(itr):
    tasu += n
    hiku += n
    if tasu*(n-1) == hiku:
        print(ttl)
        exit()

print(-1)