#!/usr/bin/perl

my@wordsInOrder;
while (<>) {
	foreach ("$_" =~ m/\w+/g) {
		push @wordsInOrder, lc($_);
	}
}

my$trypHash = {};
for ($i=0;$i < scalar(@wordsInOrder)-2; $i++) {
	$trypHash->{$wordsInOrder[$i]." ".$wordsInOrder[$i+1]." ".$wordsInOrder[$i+2]} += 1;
}
my$dupeHash = {};
for ($i=0;$i < scalar(@wordsInOrder)-1; $i++) {
	$dupeHash->{$wordsInOrder[$i]." ".$wordsInOrder[$i+1]} += 1;
}
my$oneHash = {};
for ($i=0;$i < scalar(@wordsInOrder); $i++) {
	$oneHash->{$wordsInOrder[$i]} += 1;
}

foreach my$one (sort {$oneHash->{$b} <=> $oneHash->{$a}} keys %{$oneHash} ) {
	print "$one\n";
	foreach my$two (sort {$dupeHash->{$b} <=> $dupeHash->{$a}} keys %{$dupeHash} ) {
		next unless $two =~ m/^$one/;
		print "\t$two\n";
		foreach my$three (sort {$trypHash->{$b} <=> $trypHash->{$a}} keys %{$trypHash} ) {
			next unless $three =~ m/^$two/;
			print "\t\t$three\n";
		}
	}
}