sub rec_max {
  return () unless @_;
  my ($h1, $h2) = (shift, shift);
  if (@_) {
     unshift @_, ($h1 > $h2) ? $h1 : $h2;
     &rec_max; # Try it with and without goto here
  }
  elsif (defined $h2) {
     return ($h1 > $h2) ? $h1 : $h2;
  }
}

use List::Util 'shuffle';
print rec_max shuffle(1..2000,1500..3000,3500..8000);