provided that where {TAIL ~ a component} can be classified into {HEAD ~ more than one class}, it is placed in the lower or lowest numbered class 
provided that where { TAIL ~ a component } can be classified into { HEAD ~ more than one class } , it is placed in the lower or lowest numbered class
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH