n=int(input())
a=list(map(int,input().split()))
b=list(map(int,input().split()))
c=[a[i]-b[i] for i in range(n)];c.sort();
ans=0;x=0
if (c[1]-c[0])%2==0:
	ans+=(c[1]-c[0])//2
else:
	print(-1);exit()
for i in range(1,n-1):
    d=i+1
    if (c[i+1]-c[i])%d==0:
        ans+=(c[i+1]-c[i])//d*(i+1)
        continue
    ans=-1;break
print(ans)