my $records;
while(<DATA>){
    chomp;
    my @fields = split /\s+/,$_;
    $records->{$fields[0]}{$fields[1]}{$fields[2]} += 1;
}
foreach my $level1 (keys %$records){
    foreach my $level2 (keys %{$records->{$level1}}){
	          foreach my $level3 (keys %{$records->{$level1}{$level2}}){
	    print "$level1 $level2 $level3 => ", $records->{$level1}{$level2}{$level3},"\n";
	         }
    }
}
    
	
__DATA__
sunny t a 
sunny t b 
sunny f a 
sunny f a 
sunny b b 
windy f a 
windy f b

__OUTPUT__
windy f a => 1
windy f b => 1
sunny f a => 2
sunny b b => 1
sunny t a => 1
sunny t b => 1