public int getCounts(int number) throws Exception {
		if (hs == null)
			throw new Exception("not initialized.");

		int sum = 0;
		for (Integer i : hs) {
			int j = number - i;
			if (j < i) {
				continue;
			}
			if (hs.contains(j)) {
				// System.out.println(Math.sqrt(i) + ", " + Math.sqrt(j));
				sum++;
			}
		}
		return sum;
	}