SUBROUTINE KGP4CM(P4)
C
C  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
C     Returns the 4-vector of the CM system
C
C *P4      real array (write)
C          (Px,Py,Pz,E) of CM returned to caller
C  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>