use strict;
use warnings;
use List::Util qw/max/;

my ( %words, %count );
my $file = $ARGV[0];

while (<>) {
	$words{ lc $_ }++ for split /\W+/;
}

push @{ $count{ $words{$_} } }, $_ for keys %words;
my $max = max keys %count;

print "The most frequent word(s) in $file: @{ $count{$max} }; Times seen: $max.\n"