« first day (4650 days earlier)      last day (69 days later) » 

 
6 hours later…
16:18
It's not immediately obvious, but this post is actually merely making a (nice) tangential observation/remark rather than attempting to answer the OP's questions, so I've raised a "Not an answer" flag.
It's not immediately obvious, but this post is actually merely a (valid) tangential observation/remark about the OP's wrong suggestion, rather than an attempt to reply to the OP's queries, so I've raised a "Not an answer" flag.
 
2 hours later…
18:39
c - solution-verification without specifics
19:35
C is this long proof correct?, lacking identification of which step is in doubt and why so.

« first day (4650 days earlier)      last day (69 days later) »