#!/usr/local/bin/perl

while (<>)
{
	for (split (/[^a-z]+/, "\L$_"))
	{
		++$c{$_};
	}
}

while (($w, $c) = each %c)
{
	$m = $c if $m < $c;
	$h[$c] .= "$w,";
}

while ($m > 0)
{
	print "$m\t$h[$m]\n" if $h[$m]; --$m;
}

exit;

for (sort {$c{$a}<=>$c{$b}} keys %c)
{
	print "$c{$_}\t$_\n";
}