This is similar to challenge 4, but there are multiple copies of some letter: for example there are 3 “s”s. “Words” may contain such duplicates, but replacing one S with another does not make a new “word” – so “sat” can only appear once in the list.
An additional rule is that “sh”, “th”, “ch” and “gh” and “st” can (but don’t need to) count as a single letter – so “Christmas” and “sleighride” are now valid words, despite having three consecutive consonants.
Given these constraints, how many "words" can be created?