PROGRAM compress

c	Compresses the residue numbers for solvents by combining them
c	into 'residues' of 10 atoms.

	CHARACTER*65 line

	WRITE (6, 1001) 'Enter input file name:'
1001	FORMAT (A)
	READ (5, 1001) line
	OPEN (unit=1, form='FORMATTED', status='OLD', 
	1	file=line)

	WRITE (6, 1001) 'Enter output file name:'
	READ (5, 1001) line
	OPEN (unit=2, form='FORMATTED', status='UNKNOWN',
	1	file=line)

c	Main loop

	DO WHILE (.TRUE.)
	  READ (1, 1001, end=9) line

c	Check for water

	  IF (line(4:6) .EQ. 'WAT') THEN

c	Be sure not already compressed

	    IF (line(13:13) .EQ. ' ') THEN
	      READ (line(9:11), 1002) nres
1002	      FORMAT (i3)
	      iat = MOD(nres,10)
	      nres = nres-iat+10
	      WRITE (line(8:10), 1002) nres
	      WRITE (line(13:13), 1003) iat
1003	      FORMAT (i1)
	    ELSE
	      WRITE (6, 1001) ' Solvents already compressed'
	      CLOSE (unit=1)
	      CLOSE (unit=2, disp='DELETE')
	      stop
	    endIF
	  endIF
	  WRITE (2, 1001) line
	endDO

9	CLOSE (unit=1)
	CLOSE (unit=2)
	end