$,=$/,chomp,/\b /?do{$w=(-2+length$b[0])/$';
s/ {$w}(?!\|)/$&| |/g,s/-{$w}(?!\+)/$&+ +/g for@b;
@c=();@c=(@c,$_),!$_||$_%((@b-2)/$`)or@c=(@c,0,0)for 0..@b-2;
pop@c;print@b[@c],'';@b =()}:push@b,$_ for<>
Note that non-ascii characters in the above source code will be escaped (such as \x9f).