The official editorial for E given here: https://codeforces.net/blog/entry/92739 has much less detail than the Chinese editorial (https://www.cnblogs.com/invisible-eyes/p/15003033.html). Can anyone graciously translate the Chinese editorial E solution into english?

(Or provide an English solution?). I could not find an understandable proof for E in the comments section of the editorial's blog post.

Thanks in advance.