Judgment of the district court affirming the bankruptcy court’s order confirming the Chapter 13 plan filed by the debtors is affirmed as the portion of a creditor’s secured claim attributable to the payoff of negative equity qualifies for protection from cramdown under the hanging paragraph of 11 U.S.C. section 1325(a) because negative equity financing constitutes a purchase money obligation under the UCC and thus the associated security interest satisfies the UCC’s definition of a purchase money security interest.