CHARACTER*40 INFILE1,INFILE2,FILENAME
	CHARACTER*70 ASTRING
	LOGICAL EFLG
	real*8 coor(3),com(3)
	integer*4 I,j,N,M
	CHARACTER*4   A


	WRITE(6,*) 'Calculate c o m of all atoms pdb file:'
	WRITE(6,*) 'Numerical average only:'
	WRITE(6,*) ' atomic mass, number not considred'

6	WRITE(6,*) 'ENTER NAME OF pdb file:'
	READ(5,'(A)') INFILE1
c1200	FORMAT(A)
	IF (INFILE1(:5).EQ.'     ') STOP
	  INQUIRE(FILE=INFILE1, NAME=FILENAME,EXIST=EFLG)
	  IF (.NOT.EFLG) GOTO 6
        OPEN (UNIT=2,FILE=INFILE1,STATUS='OLD')
	
	do 45 j=1,3
45	com(j)=0.
	I=1
	        
c 	read coord 
50	read(2,'(A)',end=70) ASTRING
	if ((ASTRING(1:6).ne.'ATOM  ').and.(ASTRING(1:6).ne.'HETATM')) 
     . goto 50
	read (ASTRING,51) A, A,J,(coor(j),j=1,3)
51 	format (12x,A4,A6,I4,4x,3d8.3,2f6.2)
	do 55 j=1,3
55	com(j)=com(j)+coor(j)
60	I=I+1
	goto 50
70	M=I-1
	N=3
	Write(6,*) 'finding average point of',M,' atoms'



c	form i,j th element of mtm by dotting ith into j'th column of mat.
	do 100 i=1,3
100	com(i)=com(i)/M

350	Write(6,*) 'Center of atoms:'
	Write(6,'(3F16.10)') (com(i),i=1,n)
	Write(6,*) 'to shift com to origin, pdbset with:'
	Write(6,360) (-com(i),i=1,n)
360	format ('SHIFT ',3f16.10)
	end