For certain purposes, e.g. reviewing academic articles,
it may be required that names in documents be anonymised
to hide the identiy of the person referred to.
It may also be required to preserve formatting, so that the
space taken up by the anonymised name is approximately
the same as the original name.
A simple way to do this is to replace all the letters
with Xs. Your program should carry out this operation.
More specifically you should transform the input string
by replacing each capital letter by 'X' and each lower
case letter by 'x'.
Remember not to change the file name, the input commands and the final print
statement,
otherwise our semi-automated marking program will not work and you will lose marks.