<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>poa2.txt
<TEXT>
                                                                 Exhibit 24


                             POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS that GS CAPITAL PARTNERS V
INSTITUTIONAL, L.P. (the "Company") does hereby make, constitute and
appoint each of Roger S. Begelman, Yvette Kosic, Andrea Louro DeMar, John
M. O'Rourke, Felicia J. Rector, Michael T. Seeley, and Stephen Wong (and
any other employee of The Goldman Sachs Group, Inc. or one of its
affiliates designated in writing by one of the attorneys-in-fact), acting
individually, its true and lawful attorney-in-fact, to execute and deliver
in its name and on its behalf whether the Company is acting individually or
as representative of others, any and all filings required to be made by the
Company under the Securities Exchange Act of 1934, (as amended, the "Act"),
with respect to securities which may be deemed to be beneficially owned by
the Company under the Act, giving and granting unto each said
attorney-in-fact power and authority to act in the premises as fully and to
all intents and purposes as the Company might or could do if personally
present by one of its authorized signatories, hereby ratifying and
confirming all that said attorney-in-fact shall lawfully do or cause to be
done by virtue hereof.

     THIS POWER OF ATTORNEY shall remain in full force and effect until
either revoked in writing by the undersigned or until such time as the
person or persons to whom power of attorney has been hereby granted
cease(s) to be an employee of The Goldman Sachs Group, Inc. or one of its
affiliates.

     IN WITNESS WHEREOF, the undersigned has duly subscribed these presents
as of April 12, 2006.


GS CAPITAL PARTNERS V INSTITUTIONAL, L.P.
By:   GS Advisors V, L.L.C.,
      its General Partner

By:     /s/ Adrian M. Jones
   -------------------------------------
    Name:   Adrian M. Jones
    Title:  Managing Director
</TEXT>
</DOCUMENT>
