_box =0pt
_slash=/
=-1
/catcode`/1̄2
/gdef/is_endprog /ifnext/let/next=/do_endprog /else/let/next=/relax /fi /next
/catcode`[=1 /catcode`]=2 /catcode`=12 /catcode`=12 /gdef/do_endprog#1[/egroup /egroup /egroup /end[cc]] ]
=
`_=