program reachLow; 
    read (e,w);
    s := w;
    t := {};
    u := {};
    for x in s loop
      for y in e { x } loop
	if y notin t then
          t with := y;
	  if y notin s then
            u with := y;
	  end if;
	end if;
      end loop;
    end loop;
    while exists x in u | true loop
      for y in e { x } loop
        if y notin t then
	  if y notin s then
	    u with := y;
	  end if;
	  t with := y;
        end if;
      end loop;
      if x in t then
	u less := x;
      end if;
      s with := x;
    end loop;
    print(s);
  end;