Form: SC 13G/A

Schedule filed to report acquisition of beneficial ownership of 5% or more of a class of equity securities by passive investors and certain institutions

March 10, 2008

JOINT FILING AGREEMENT

Published on March 10, 2008



EXHIBIT I



JOINT FILING AGREEMENT
----------------------




Each of the undersigned hereby agrees that the Schedule 13G
filed herewith is filed jointly, pursuant to Rule 13d-1(f)(1)
of the Securities Exchange Act of 1934, as amended on behalf of
each of them.


Dated: March 10, 2008

AXA Financial, Inc.



BY: /s/ Alvin H. Fenichel
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Alvin H. Fenichel
Senior Vice President and Controller



AXA Assurances I.A.R.D. Mutuelle; AXA Assurances Vie
Mutuelle; as a group, and AXA

Signed on behalf of each of the above entities



BY: /s/ Alvin H. Fenichel
-----------------------------------------
Alvin H. Fenichel
Attorney-in-Fact