SCHEDULE 13G

EXHIBIT A

RELEVANT SUBSIDIARIES AND MEMBERS OF FILING GROUP

PARENT HOLDING COMPANIES OR CONTROL PERSONS:

Warren E. Buffett (an individual who may be deemed to control Berkshire Hathaway Inc.)

Berkshire Hathaway Inc.

GEICO Corporation

INSURANCE COMPANIES AS DEFINED IN SECTION 3(a)(19) OF THE ACT:

National Indemnity Company

Berkshire Hathaway Homestate Insurance Company

British Insurance Company of Cayman

GEICO Advantage Insurance Company

GEICO Secure Insurance Company

GEICO Choice Insurance Company

National Fire & Marine Insurance Company