import java.util.List;

class Occupant {
	public Occupant(String name, int age) {
		setName(name);
		setAge(age);
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public int getAge() {
		return age;
	}

	private int age;
	private String name;
}

class Room {
	public Room(int roomNo) {
		this(null, roomNo;
	}

	public Room(Occupant o, int roomNo) {
		setOccupant(o);
		setRoomNo(roomNo);
	}

	public void setOccupant(Occupant o) {
		this.o = o;
	}

	public Occupant getOccupant() {
		return o;
	}

	private void setRoomNo(int roomNo) {
		ROOM_NO = roomNo;
	}

	public int getRoomNo() {
		return ROOM_NO;
	}

	private Occupant o;
	private final int ROOM_NO;
}

/* overhead waste :( oh well... */
class RoomOperations {
	public static void setRooms(List<Room> rooms) {
		this.rooms = rooms;
	}

	public static List getRooms() {
		return rooms;
	}

	public static int findVacantRoom() {
		for(Room r : getRooms().toArray(new Room[0]))
			if(r.getOccupant() == null)
				return r.getRoomNo();
		return -1;
	}

	private static List rooms;
}