use strict;                         # complain about errors
my %lexicon;                        # collect unique strings
while (<>) {                        # read each line input
   my @words =                      # gather list of words
      map { s/^\W+|\W+$//g; $_ }    # strip punctuation
      split /\s+/;                  # break line at spaces
   foreach my $word (@words) {      # each word in the line
      $lexicon{$word}++;            # should be counted
   }
}
print "$_: $lexicon{$_}\n"          # show word and count
   foreach (sort keys %lexicon);    # for all words in order