public int NumShips(int playerID) {
		int numShips = 0;
		for (Planet p : planets) {
			if (p.Owner() == playerID) {
				numShips += p.NumShips();
			}
		}
		for (Fleet f : fleets) {
			if (f.Owner() == playerID) {
				numShips += f.NumShips();
			}
		}
		return numShips;
	}