sc13da406297101_04272012.htm

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON STARBOARD VALUE AND OPPORTUNITY MASTER FUND LTD
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION CAYMAN ISLANDS
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 2,586,926
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 2,586,926
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,586,926
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 2.8%
14	TYPE OF REPORTING PERSON CO

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON STARBOARD VALUE AND OPPORTUNITY S LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 891,610
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 891,610
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 891,610
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) Less than 1%
14	TYPE OF REPORTING PERSON OO

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON STARBOARD VALUE LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 4,966,000
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 4,966,000
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,966,000
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3%
14	TYPE OF REPORTING PERSON PN

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON STARBOARD VALUE GP LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 4,966,000
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 4,966,000
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,966,000
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3%
14	TYPE OF REPORTING PERSON OO

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON STARBOARD PRINCIPAL CO LP
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 4,966,000
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 4,966,000
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,966,000
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3%
14	TYPE OF REPORTING PERSON PN

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON STARBOARD PRINCIPAL CO GP LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION DELAWARE
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 4,966,000
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 4,966,000
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,966,000
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3%
14	TYPE OF REPORTING PERSON OO

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON JEFFREY C. SMITH
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 4,966,000
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 4,966,000
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,966,000
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3%
14	TYPE OF REPORTING PERSON IN

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON MARK R. MITCHELL
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 4,966,000
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 4,966,000
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,966,000
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3%
14	TYPE OF REPORTING PERSON IN

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON PETER A. FELD
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 4,966,000
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 4,966,000
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,966,000
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 5.3%
14	TYPE OF REPORTING PERSON IN

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON DENNIS A. MILLER
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS PF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 2,700
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 2,700
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,700
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) Less than 1%
14	TYPE OF REPORTING PERSON IN

CUSIP NO. 00184X105

1	NAME OF REPORTING PERSON JAMES A. WARNER
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS PF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 581
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 581
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 581
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) Less than 1%
14	TYPE OF REPORTING PERSON IN

CUSIP NO. 00184X105

The following constitutes Amendment No. 4 to the Schedule 13D filed by the undersigned (“Amendment No. 4”). This Amendment No. 4 amends the Schedule 13D as specifically set forth herein.

Item 2.

Identity and Background.

Item 2 is hereby amended to add the following:

As previously disclosed, on February 24, 2012, Starboard V&O Fund delivered a letter to the Issuer nominating Ronald S. Epstein, Steven B. Fink, Dennis A. Miller, Jeffrey C. Smith and James A. Warner for election to the Board of Directors of the Issuer at 2012 annual meeting of the Issuer’s shareholders (the “2012 Annual Meeting”). As more fully described in the Reporting Persons’ revised preliminary proxy statement filed with the Securities and Exchange Commission on April 27, 2012, the Reporting Persons are proceeding to seek the election of Messrs. Miller, Smith and Warner at the 2012 Annual Meeting. As such, Messrs. Epstein and Fink will no longer be members of the Section 13(d) group. The remaining Reporting Persons will continue filing as a group statements on Schedule 13D with respect to their beneficial ownership of securities of the Issuer to the extent required by applicable law. Each of the remaining Reporting Persons is party to the Joint Filing and Solicitation Agreement, as amended, and as further described in Item 6.

Item 3.

Source and Amount of Funds or Other Consideration.

Item 3 is hereby amended and restated to read as follows:

The Shares purchased by each of Starboard V&O Fund and Starboard LLC and held in the Starboard Value LP Accounts were purchased with working capital (which may, at any given time, include margin loans made by brokerage firms in the ordinary course of business) in open market purchases, except as otherwise noted, as set forth in Schedule A, which is incorporated by reference herein. The aggregate purchase price of the 2,586,926 Shares beneficially owned by Starboard V&O Fund is approximately $36,563,234, excluding brokerage commissions. The aggregate purchase price of the 891,610 Shares beneficially owned by Starboard LLC is approximately $12,426,618, excluding brokerage commissions. The aggregate purchase price of the 1,487,464 Shares held in the Starboard Value LP Accounts is approximately $22,039,229, excluding brokerage commissions.

The 581 Shares directly owned by Mr. Warner are held in a joint account and were purchased in the open market with personal funds. The aggregate purchase price of the Shares directly owned by Mr. Warner is approximately $9,857, excluding brokerage commissions.

The 2,700 Shares directly owned by Mr. Miller were purchased in the open market with personal funds. The aggregate purchase price of the Shares directly owned by Mr. Miller is approximately $49,628, including brokerage commissions.

Item 5.

Interest in Securities of the Issuer.

Items 5(a)-(c) are hereby amended and restated to read as follows:

The aggregate percentage of Shares reported owned by each person named herein is based upon 93,451,510 Shares outstanding, as of April 18, 2012, which is the total number of Shares outstanding as reported in the Issuer’s Definitive Proxy Statement for the 2012 annual meeting of shareholders of the Issuer filed with the Securities and Exchange Commission on April 20, 2012.

CUSIP NO. 00184X105

A.	Starboard V&O Fund

(a)

As of the close of business on April 26, 2012, Starboard V&O Fund beneficially owned 2,586,926 Shares.

Percentage: Approximately 2.8%

(b)

1. Sole power to vote or direct vote: 2,586,926

2. Shared power to vote or direct vote: 0

3. Sole power to dispose or direct the disposition: 2,586,926

4. Shared power to dispose or direct the disposition: 0

(c)

Starboard V&O Fund has not entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D.

B.	Starboard LLC

(a)

As of the close of business on April 26, 2012, Starboard LLC beneficially owned 891,610 Shares.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 891,610

2. Shared power to vote or direct vote: 0

3. Sole power to dispose or direct the disposition: 891,610

4. Shared power to dispose or direct the disposition: 0

(c)

Starboard LLC has not entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D.

C.	Starboard Value LP

(a)

As of the close of business on April 26, 2012, 1,487,464 Shares were held in the Starboard Value LP Accounts. Starboard Value LP, as the investment manager of Starboard V&O Fund and the Manager of Starboard LLC, may be deemed the beneficial owner of the (i) 2,586,926 Shares owned by Starboard V&O Fund and (ii) 891,610 Shares owned by Starboard LLC.

Percentage: Approximately 5.3%

(b)

1. Sole power to vote or direct vote: 4,966,000

2. Shared power to vote or direct vote: 0

3. Sole power to dispose or direct the disposition: 4,966,000

4. Shared power to dispose or direct the disposition: 0

(c)

Starboard Value LP has not directly entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D. The transactions in the Shares through the Starboard Value LP Managed Accounts since the filing of Amendment No. 3 to the Schedule 13D are set forth in Schedule A and are incorporated herein by reference.

CUSIP NO. 00184X105

D.	Starboard Value GP

(a)

Starboard Value GP, as the general partner of Starboard Value LP, may be deemed the beneficial owner of the (i) 2,586,926 Shares owned by Starboard V&O Fund, (ii) 891,610 Shares owned by Starboard LLC and (iii) 1,487,464 Shares held in the Starboard Value LP Accounts.

Percentage: Approximately 5.3%

(b)

1. Sole power to vote or direct vote: 4,966,000

2. Shared power to vote or direct vote: 0

3. Sole power to dispose or direct the disposition: 4,966,000

4. Shared power to dispose or direct the disposition: 0

(c)

Starboard Value GP has not entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D. The transactions in the Shares through the Starboard Value LP Managed Accounts since the filing of Amendment No. 3 to the Schedule 13D are set forth in Schedule A and are incorporated herein by reference.

E.	Principal Co

(a)

Principal Co, as a member of Starboard Value GP, may be deemed the beneficial owner of the (i) 2,586,926 Shares owned by Starboard V&O Fund, (ii) 891,610 Shares owned by Starboard LLC and (iii) 1,487,464 Shares held in the Starboard Value LP Accounts.

Percentage: Approximately 5.3%

(b)

1. Sole power to vote or direct vote: 4,966,000

2. Shared power to vote or direct vote: 0

3. Sole power to dispose or direct the disposition: 4,966,000

4. Shared power to dispose or direct the disposition: 0

CUSIP NO. 00184X105

(c)

Principal Co has not entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D. The transactions in the Shares through the Starboard Value LP Managed Accounts since the filing of Amendment No. 3 to the Schedule 13D are set forth in Schedule A and are incorporated herein by reference.

F.	Principal GP

(a)

Principal GP, as the general partner of Principal Co, may be deemed the beneficial owner of the (i) 2,586,926 Shares owned by Starboard V&O Fund, (ii) 891,610 Shares owned by Starboard LLC and (iii) 1,487,464 Shares held in the Starboard Value LP Accounts.

Percentage: Approximately 5.3%

(b)

1. Sole power to vote or direct vote: 4,966,000

2. Shared power to vote or direct vote: 0

3. Sole power to dispose or direct the disposition: 4,966,000

4. Shared power to dispose or direct the disposition: 0

(c)

Principal GP has not entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D. The transactions in the Shares through the Starboard Value LP Managed Accounts since the filing of Amendment No. 3 to the Schedule 13D are set forth in Schedule A and are incorporated herein by reference.

G.	Messrs. Smith, Mitchell and Feld

(a)

Each of Messrs. Smith, Mitchell and Feld, as a member of Principal GP and as a member of each of the Management Committee of Starboard Value GP and the Management Committee of Principal GP, may be deemed the beneficial owner of the (i) 2,586,926 Shares owned by Starboard V&O Fund, (ii) 891,610 Shares owned by Starboard LLC and (iii) 1,487,464 Shares held in the Starboard Value LP Accounts.

Percentage: Approximately 5.3%

(b)

1. Sole power to vote or direct vote: 0

2. Shared power to vote or direct vote: 4,966,000

3. Sole power to dispose or direct the disposition: 0

4. Shared power to dispose or direct the disposition: 4,966,000

(c)

None of Messrs. Smith, Mitchell or Feld has entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D. The transactions in the Shares through the Starboard Value LP Managed Accounts since the filing of Amendment No. 3 to the Schedule 13D are set forth in Schedule A and are incorporated herein by reference.

H.	Mr. Warner

(a)

As of the close of business on April 26, 2012, Mr. Warner directly owned 581 Shares. Mr. Warner, as a member of a “group” with the other Reporting Persons for the purposes of Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), may be deemed the beneficial owner of the Shares directly owned by the other Reporting Persons. Mr. Warner disclaims beneficial ownership of such Shares.

Percentage: Less than 1%

(b)

1. Sole power to vote or direct vote: 0

2. Shared power to vote or direct vote: 581

3. Sole power to dispose or direct the disposition: 0

4. Shared power to dispose or direct the disposition: 581

(c)

Mr. Warner has not entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D.

I.	Mr. Miller

(a)

As of the close of business on April 26, 2012, Mr. Miller directly owned 2,700 Shares. Mr. Miller as a member of a “group” with the other Reporting Persons for the purposes of Section 13(d)(3) of the Exchange Act, may be deemed the beneficial owner of the Shares directly owned by the other Reporting Persons. Mr. Miller disclaims beneficial ownership of such Shares.

Percentage: Less than 1%

CUSIP NO. 00184X105

(b)

1. Sole power to vote or direct vote: 2,700

2. Shared power to vote or direct vote: 0

3. Sole power to dispose or direct the disposition: 2,700

4. Shared power to dispose or direct the disposition: 0

(c)

Mr. Miller has not entered into any transactions in the Shares since the filing of Amendment No. 3 to the Schedule 13D.

Item 6.

Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.

Item 6 is hereby amended to add the following:

On April 27, 2012, the Reporting Persons entered into Amendment No. 1 to the Joint Filing and Solicitation Agreement. A copy of this agreement is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Item 7.

Material to be Filed as Exhibits.

Item 7 is hereby amended to add the following exhibit:

99.1

Amendment No. 1 to the Joint Filing and Solicitation Agreement.

CUSIP NO. 00184X105

SIGNATURES

After reasonable inquiry and to the best of his knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated: April 27, 2012

STARBOARD VALUE AND OPPORTUNITY MASTER FUND LTD

By: Starboard Value LP,

its investment manager

STARBOARD VALUE AND OPPORTUNITY S LLC

By: Starboard Value LP,

its manager

STARBOARD VALUE LP

By: Starboard Value GP LLC,

its general partner

STARBOARD VALUE GP LLC

By: Starboard Principal Co LP,

its member

STARBOARD PRINCIPAL CO LP

By: Starboard Principal Co GP LLC,

its general partner

STARBOARD PRINCIPAL CO GP LLC



By:	/s/ Jeffrey C. Smith
	Name:	Jeffrey C. Smith
	Title:	Authorized Signatory

/s/ Jeffrey C. Smith

JEFFREY C. SMITH

Individually and as attorney-in-fact for Mark R.

Mitchell, Peter A. Feld, Dennis A. Miller and

James A. Warner

CUSIP NO. 00184X105

SCHEDULE A

Transactions in the Shares Since the Filing of Amendment No. 3 to the Schedule 13D

Shares of Common Stock

Purchased

Price Per

Share($)

Date of

Purchase

STARBOARD VALUE LP

(Through the Starboard Value LP Accounts)

50,000	24.6612	04/12/2012