my ($session_id, $last_action_date, $last_action_time) = (0,0,0);
if ($session =~ /^(\d\d)-(\d{10})-(\d{8})$/) {
  $session_id = $1;
  $last_action_date = $2;
  $last_action_time = $3;
}
else {
  # print some kind of warning -- the session ID didn't match my regex!
}