sub move_disks_from_one_peg_to_another_peg_using_a_third
{
   my ($n, $peg_a, $peg_b, $peg_c) = @_;
   if ($n == 1) 
   {
      print "Move disk #1 from $peg_a to $peg_b.\n";
      return;
   } 
   else 
   {
      move_disks_from_one_peg_to_another_peg_using_a_third($n-1, $peg_a, $peg_c, $peg_b);
      print "Move disk #$n from $peg_a to $peg_b.\n";
      move_disks_from_one_peg_to_another_peg_using_a_third($n-1, $peg_c, $b, $peg_a);
      return;
   }
}