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
	character*6 chain1, chain2
	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:'
	READ(5,1200) INFILE1
	IF (INFILE1(:5).EQ.'     ') STOP
	  INQUIRE(FILE=INFILE1, NAME=FILENAME,EXIST=EFLG)
	  IF (.NOT.EFLG) GOTO 6
        OPEN (UNIT=2,FILE=INFILE1,STATUS='OLD')
8	WRITE(6,*) 'ENTER NAME OF 2nd pdb file (identical atom order):'
	READ(5,1200) INFILE2
	IF (INFILE2(:5).EQ.'     ') STOP
	  INQUIRE(FILE=INFILE2, NAME=FILENAME,EXIST=EFLG)
	  IF (.NOT.EFLG) GOTO 8
        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
	write(6,*)'Threshold (only distances greater will be printed)'
	read(5,*)thresh
	 dmax=-1.0
	 mres1=-999
	 mres2=-999
         sum=0
	 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
	read (ASTRING,51) AT1, chain1,nres1,(m1(i),I=1,3)
c	DECODE(70,51,ASTRING) AT1, chain1,nres1,(m1(i),I=1,3)
51 	format (12x,A4,A6,I4,4x,3d8.3,2f6.2)
c	write (6,*) astring
c	write (6,*)at1,nres1,(m1(i),I=1,3)
c	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
	READ(ASTRING,51) AT2,chain2,nres2,(m2(i),I=1,3)
	if (nres2.ne.nfirst2) goto 60
c	write(6,111) (m2(i,k),I=1,3)


	goto 80
70	read(2,1200,end=1160) ASTRING
	if ((ASTRING(1:6).ne.'ATOM  ').and.(ASTRING(1:6).ne.'HETATM')) 
     . goto 70
	read (ASTRING,51) AT1, chain1,nres1,(m1(i),I=1,3)

75	read(3,1200,end=1160) ASTRING
	if ((ASTRING(1:6).ne.'ATOM  ').and.(ASTRING(1:6).ne.'HETATM')) 
     . goto 75
	read (ASTRING,51)  AT2, chain2,nres2,(m2(i),I=1,3)

C123456789012345678901234567890
CATOM      1  CB  THR A   1     118.652  75.582 117.301  1.00 85.64          


80	if (nres1.gt.nlast1) goto 1160
	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,x,sum
C110	if (d.gt.thresh) write (6,111) at1,nres1,char(9),at2,nres2,char(9),d
110	if (d.gt.thresh) write (6,111) at1,chain1,nres1,char(9),at2,chain2,nres2,char(9),d
C111	format (' ',2i5,16f5.1)
C111	format (' ',2(a4,i3,a1),16f10.4)
111	format (' ',2(a4,a6,i4,a1),16f10.4)

	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