($N,$M,$K)=glob<>;
@_=<>;
@d=glob pop@_;
/ .* /,push@{$'+0},[$`,$&],[$&,$`]for@_;
@g=[0,(1)x$N];
for(@d){
	for(@$_){
		$g[$i+1][@$_[1]]|=$g[$i][@$_[0]]
	}
	++$i
}
@g=grep@{$g[$K]}[$_],1..$N;
print@g."\n@g"