PROGRAM compress

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

	CHARACTER*66 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='NEW',
	1	file=line)

	DO WHILE (.TRUE.)
	  READ (1, 1001, end=9) line
	  IF (line(18:20) .EQ. 'WAT') THEN
	    IF (line(23:23) .EQ. ' ') THEN
	      READ (line(24:26), 1002) nres
1002	      FORMAT (i3)
	      IF (nres .LT. 900) THEN
	        iat = MOD(nres,10)
	        nres = nres - iat + 10
	        WRITE (line(24:26), 1002) nres
	        WRITE (line(15:15), 1003) iat
1003	        FORMAT (i1)
	      endIF
	    ELSE
	      READ (line(23:25), 1002) nres
	      IF (nres .LT. 900) THEN
	        iat = MOD(nres,10)
	        nres = nres - iat + 10
	        WRITE (line(23:25), 1002) nres
	        WRITE (line(15:15), 1003) iat
	      endIF
	    endIF
	  endIF
	  WRITE (2, 1001) line
	endDO

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