Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F1,F2	Oct 7, 2015	S	853,920	$21.50	D	14,557,836	I	By Vestar Capital Partners V, L.P.
Common Stock^F1,F3	Oct 7, 2015	S	234,850	$21.50	D	4,003,741	I	By Vestar Capital Partners V-A, L.P.
Common Stock^F1,F4	Oct 7, 2015	S	30,922	$21.50	D	527,168	I	By Vestar Capital Partners V-B, L.P.
Common Stock^F1,F5	Oct 7, 2015	S	30,304	$21.50	D	516,634	I	By Vestar/NMH Investors, LLC

Table II — derivative securities

No Table II lines on this filing.

Explanation of responses

F1Represents shares of common stock sold in an underwritten offering. The sale price received by the reporting person will be reduced by the underwriters' commission of $1.12875 per share.
F2These shares are held directly by the Vestar Capital Partners V, L.P. (the "Fund"). Vestar Associates V, L.P ("Vestar Associates V") is the general partner of the Fund. Vestar Managers V Ltd. ("VMV") is the general partner of Vestar Associates V. Mr. O'Connell is the sole director of VMV. As a result of these relationships, each of Vestar Associates V, VMV and Mr. O'Connell may be deemed to have beneficial ownership of the shares held directly by the Fund. Each of Vestar Associates V, VMV and Mr. O'Connell disclaims beneficial ownership of the securities beneficially owned by the Fund, except to the extent of its or his respective pecuniary interest therein.
F3These shares are held directly by Vestar Capital Partners V-A, L.P. ("Fund V-A"). Vestar Associates V is the general partner of Fund V-A. VMV is the general partner of Vestar Associates V. Mr. O'Connell is the sole director of VMV. As a result of these relationships, each of Vestar Associates V, VMV and Mr. O'Connell may be deemed to have beneficial ownership of the shares held directly by Fund V-A. Each of Vestar Associates V, VMV and Mr. O'Connell disclaims beneficial ownership of the securities beneficially owned by Fund V-A, except to the extent of its or his respective pecuniary interest therein.
F4These shares are held directly by Vestar Capital Partners V-B, L.P. ("Fund V-B"). Vestar Associates V is the general partner of Fund V-B. VMV is the general partner of Vestar Associates V. Mr. O'Connell is the sole director of VMV. As a result of these relationships, each of Vestar Associates V, VMV and Mr. O'Connell may be deemed to have beneficial ownership of the shares held directly by Fund V-B. Each of Vestar Associates V, VMV and Mr. O'Connell disclaims beneficial ownership of the securities beneficially owned by Fund V-B, except to the extent of its or his respective pecuniary interest therein.
F5These shares are held directly by Vestar/NMH Investors. The Fund is the managing member of Vestar/NMH Investors, and Vestar Executives V, L.P. ("Vestar Executives V") and Vestar Co-Invest V, L.P. ("Vestar Co-Invest V") are members of Vestar/NMH Investors. Vestar Associates V is the general partner of the Fund and Vestar Executives V. VMV is the general partner of Vestar Associates V and Vestar Co-Invest V. Mr. O'Connell is the sole director of VMV. As a result of these relationships, each of Vestar Executives V, Vestar Co-Invest V, Vestar Associates V, VMV and Mr. O'Connell may be deemed to have beneficial ownership of the shares held directly by Vestar/NMH Investors. Each of Vestar Executives V, Vestar Co-Invest V, Vestar Associates V, VMV and Mr. O'Connell disclaims beneficial ownership of the securities beneficially owned by Vestar/NMH Investors, except to the extent of its or his respective pecuniary interest therein.