After reaching the last ordered path, {HEAD ~ the first node} of {TAIL ~ each path} in the group is removed 
of
After reaching the last ordered path , { HEAD ~ the first node } of { TAIL ~ each path } in the group is removed
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH