N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

diff = []

for i in range(N):
    t = B[i] - A[i]

    diff.append(t)

diff.sort()

t = diff[0]

def calc():
    res = 0.0
    for obj in diff:
        if obj == t:
            pass
        else:
            res += (abs(t) + obj) / 2

    return res

res = calc()
result = -1

if res.is_integer():
    r = int(res)
    if abs(t) == r:
        result = r
    elif r == 0:
        t = t // (N-2) * N
        res = calc()
        if res.is_integer():
            r = int(res)
            if abs(t) == r:
                result = abs(r)

    else:
        ta = -diff[0] + diff[N - 1]
        if ta >= 0:
            tt = ta * (N-2)
            for i in range(N):
                diff[i] += tt

            t = diff[0]
            res = calc()
            if res.is_integer():
                r = int(res)
                if abs(t) == r:
                    result = abs(r + ta * N)

print(result)