program MAKE_DATA_FILES

       implicit NONE

       character*80       infile
       character*80       outfile
       character*80       line

       integer            first, last, frame
       integer            ios, inlun, outlun

       double precision   x, y, dx, dy, deriv

c  begin

       inlun = 20
       outlun = 30

       write (*, *) 'enter input file name'
       read (*, fmt='(a80)') infile
       open (unit=inlun, file = infile,
     & form = 'formatted', status = 'old')

       write (*, *) 'enter first frame'
       read (*, *) first
       write (*, *) 'enter last frame'
       read (*, *) last

       write (*, *) 'enter output file name'
       read (*, fmt='(a80)') outfile
       open (unit=outlun, file = outfile,
     & form = 'formatted', status = 'unknown')

       ios = 0
       frame = 0
       do while ( ios .eq. 0 )
         read (inlun, fmt = '(a80)', iostat = ios) line
         if (ios .eq. 0 .and. .not. (line(1:1) .eq. '!') ) then
           if ( line(1:7) .eq. '# frame' ) then
             read(line(9:12), fmt='(i4)') frame
           else
             read (line, *) x, y, dx, dy, deriv 
           endif
           if ( frame .ge. first .and. frame .le. last ) then
             write (outlun, fmt='(a80)') line
           endif
         endif
       end do

       close (inlun)
       close (outlun)

       stop
       END