{HEAD ~ a kind} of package selecting means of selectively specifying {TAIL ~ the kind} of packages to be packaged 
{ HEAD ~ a kind } of package selecting means of selectively specifying { TAIL ~ the kind } of packages to be packaged
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH