@x=sort{(split/ /,$a)[2]<=>(split/ /,$b)[2]}<>;$y{a}=1;X:{do{/(\w+) (\w+)/;$1 ne'T'and$y{$1}&&!$y{$2}++||$y{$2}&&!$y{$1}++and$_="T $_",redo X}for@x}chomp,/T/ ||($_="F $_"),print"$_
"for@x