there are about 100 directories in which are the html files

in each directory we find all the prefixes, (for example in the 042
directory):

one 042.html file
several 042[a-z].html files (up to 26), each of them are linked to many
042[04200001-042XXXXX).html files (up to 50 , X are numbers)
few circons[01-xx].html files, (the average is about 5)

and i need only the circons[01-25].html files