CHARACTER*40 INFILE1,INFILE2,FILENAME
	CHARACTER*70 ASTRING
	LOGICAL EFLG
	real*8 M1(3),M2(3),d
	INTEGER*4 I,J,k
	character*1 tbstr
	character*4 at1,at2
	tbstr=char(9)

1200	FORMAT(A)

	write(6,*)'Now ignores non-ATOM records'
c 	read operator into m2
6	WRITE(6,*) 'ENTER NAME OF 1st pdb file (CA atom recds only):'
	READ(5,1200) INFILE1
	IF (INFILE1(:5).EQ.'     ') STOP
	  INQUIRE(FILE=INFILE1, NAME=FILENAME,EXIST=EFLG)
	  IF (.NOT.EFLG) GOTO 6
c        OPEN (UNIT=2,FILE=INFILE1,STATUS='OLD',READONLY)
        OPEN (UNIT=2,FILE=INFILE1,STATUS='OLD')
8	WRITE(6,*) 'ENTER NAME OF 2nd pdb file (CA atom recds only):'
	READ(5,1200) INFILE2
	IF (INFILE2(:5).EQ.'     ') STOP
	  INQUIRE(FILE=INFILE2, NAME=FILENAME,EXIST=EFLG)
	  IF (.NOT.EFLG) GOTO 8
c        OPEN (UNIT=3,FILE=INFILE2,STATUS='OLD',READONLY)
        OPEN (UNIT=3,FILE=INFILE2,STATUS='OLD')
	dmax=0.

	write(6,*)'First and last residues in ',infile1,'?'
	read (5,*) nfirst1,nlast1
	write(6,*)'First residue in ',infile2,'?'
	read (5,*) nfirst2
	n=0
c 	read coord         
50	read(2,1200,end=1160) ASTRING
	if ((ASTRING(1:6).ne.'ATOM  ').and.(ASTRING(1:6).ne.'HETATM')) 
     . goto 50
c	DECODE(70,51,ASTRING) AT1,nres1,(m1(i),I=1,3)
 	read (ASTRING,51)     AT1,nres1,(m1(i),I=1,3)
51 	format (12x,A4,6X,I4,4x,3d8.3,2f6.2)
c	at1=ASTRING(13:16)
	write (6,*) astring
	write (6,*)at1,nres1,(m1(i),I=1,3)
	write(6,111) AT1,nres1,(m1(i),I=1,3)
	if (nres1.ne.nfirst1) goto 50

c 	read coord         
60	read(3,1200,end=1160) ASTRING
	if ((ASTRING(1:6).ne.'ATOM  ').and.(ASTRING(1:6).ne.'HETATM')) 
     . goto 60
c	DECODE(70,51,ASTRING) AT2,nres2,(m2(i),I=1,3)
 	read (ASTRING,51)     AT2,nres2,(m2(i),I=1,3)
	write (6,*)at2,nres2,(m1(i),I=1,3)
	if (nres2.ne.nfirst2) goto 60
	at2=ASTRING(13:16)
c	write(6,111) (m2(i,k),I=1,3)


	goto 80
70	read(2,51,end=1160) AT1,nres1,(m1(i),I=1,3)
	read(3,51,end=1160) AT2,nres2,(m2(i),I=1,3)



80	x=0.
	do 90 i=1,3
90	x=x+(m1(i)-m2(i))**2
100	d=sqrt(x)
	sum=sum+x
	n=n+1
	if (d.gt.dmax) then
	 dmax=d
	 mres1=nres1
	 mres2=nres2
	 endif
C110	write (6,111) at1,nres1,at2,nres2,d
110	write (6,111) at1,nres1,char(9),at2,nres2,char(9),d
C111	format (' ',2i5,16f5.1)
111	format (' ',2(a4,i3,a1),16f10.4)

	if (nres1.ne.nlast1) goto 70

1160	CLOSE(UNIT=2)
	write(6,*)'These ',n,' Atoms have RMS diff ',sqrt(sum/n)
	write (6,*) 'Max diff ',dmax,' between',mres1,mres2
	END