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();d=0;ans=0
for i in range(n-1):
    d+=2
    if (c[i+1]-c[i])%d==0:
        ans+=(c[i+1]-c[i])//2*(i+1)
        continue
    ans=-1;break
print(ans)