EXHIBIT A

                             JOINT FILING AGREEMENT

                            PURSUANT TO RULE 13d-1(k)

           The undersigned acknowledge and agree that the foregoing statement on
Schedule 13D is filed on behalf of each of the undersigned and that all
subsequent amendments to this statement on Schedule 13D may be filed on behalf
of each of the undersigned without the necessity of filing additional joint
filing agreements. The undersigned acknowledge that each shall be responsible
for the timely filing of such amendments, and for the completeness and accuracy
of the information concerning him or it contained herein and therein, but shall
not be responsible for the completeness and accuracy of the information
concerning the others, except to the extent that he or it knows or has reason to
believe that such information is inaccurate.

Dated:  December 4, 2006


                                 CLINTON GROUP, INC.

                                 By: /s/ Francis Ruchalski
                                     ---------------------------
                                     Name:  Francis Ruchalski
                                     Title: Comptroller


                                 CLINTON MULTISTRATEGY MASTER FUND, LTD.
                                 By: Clinton Group, Inc. its investment
                                 manager

                                 By: /s/ Francis Ruchalski
                                     ---------------------------
                                     Name:  Francis Ruchalski
                                     Title: Comptroller


                               /s/ George E. Hall
                                 ------------------------------
                                 George E. Hall


                                 /s/ Conrad Bringsjord
                                 ------------------------------
                                Conrad Bringsjord