sub split_into_three {
   my $first = @_;
   my $last = int($first / 3);
   $first -= $last;
   $first -= int($first / 2);

   return [ @_[0..$first-1] ],
          [ @_[$first..$#_-$last] ],
          [ @_[$#_-$last+1..$#_] ];
}

my ($first, $second, $third) = split_into_three(@everything);

my @buckets = split_into_three('a'..'z');
print join("\n", map { join(" ", @{$_}) } @buckets), "\n";

# a b c d e f g h i
# j k l m n o p q r
# s t u v w x y z