No problem.
The key thing is the regular expression (..)(?!$)
This means: Match any 2 chars ".." and remember them "()" if they are
not followed by the string's end "(?!$)".
If such a match is found, it is replaced by the 2 chars found "$1" and a slash appended, so "$1/".
Hmmm... Not so well my explanation, I think. The idea is to find any two characters and append a slash to them The only exception is at the end of the string where no slash may be added.
This works well for your data, but as soon as you got other data, it will produce nonsense by inserting slashes every 2 characters.
$\=~s;s*.*;q^|D9JYJ^^qq^\//\\\///^;ex;print