Exhibit 4

JOINT FILING AGREEMENT

The undersigned acknowledge and agree that the foregoing statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13D shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the other entities or persons, except to the extent that it knows or has reason to believe that such information is inaccurate.

DATED: March 29, 2017

BLUEMOUNTAIN CAPITAL MANAGEMENT, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUE MOUNTAIN CREDIT GP, LLC
BY: BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUE MOUNTAIN CA MASTER FUND GP, LTD.
By:	/s/ ANDREW FELDSTEIN
Name: Andrew Feldstein, Director
BLUE MOUNTAIN CREDIT ALTERNATIVES MASTER FUND L.P.
BY: BLUE MOUNTAIN CA MASTER FUND GP, LTD.
By:	/s/ ANDREW FELDSTEIN
Name: Andrew Feldstein, Director
BLUEMOUNTAIN LONG/SHORT CREDIT GP, LLC
BY: BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer

BLUEMOUNTAIN GUADALUPE PEAK FUND L.P.
BY: BLUEMOUNTAIN LONG/SHORT CREDIT GP, LLC
BY: BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUEMOUNTAIN CREDIT OPPORTUNITIES GP I, LLC
BY: BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUEMOUNTAIN CREDIT OPPORTUNITIES MASTER FUND I L.P.
BY: BLUEMOUNTAIN CREDIT OPPORTUNITIES GP I, LLC
BY: BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUEMOUNTAIN STRATEGIC CREDIT GP, LLC
BY: BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUEMOUNTAIN STRATEGIC CREDIT MASTER FUND L.P.
BY: BLUEMOUNTAIN STRATEGIC CREDIT GP, LLC
BY: BLUEMOUNTAIN GP HOLDINGS, LLC
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUEMOUNTAIN MONTENVERS GP S.à r.l.
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer
BLUEMOUNTAIN MONTENVERS MASTER FUND SCA SICAV-SIF
BY: BLUEMOUNTAIN MONTENVERS GP S.à r.l.
By:	/s/ ERIC M. ALBERT
Name: Eric M. Albert, Chief Compliance Officer