($n,$m)=glob<>;
for(1..$m){
	($g,$r)=glob<>;
	$h[$g]=<>;
}
for(1..32){
	hoge:
	for$g(1..$n){
		for($h[$g]=~/\d+/g){
			if(!$u[$_]){
				next hoge;
			}
		}
		$u[$g]=1;
	}
}
print 0+grep$_,@u;