public void backtrack(int[] nums, int k, int n, int lvl, int sum, int count) {
		if (count == k && sum == n) {
			List<Integer> newList = new ArrayList<Integer>(list);
			result.add(newList);
			return;
		} else if (sum > n || lvl > 8) {
			return;
		} else {
			list.add(nums[lvl]);
			backtrack(nums, k, n, lvl + 1, sum + nums[lvl], count + 1);
			list.remove(list.size() - 1);
			backtrack(nums, k, n, lvl + 1, sum, count);
		}

	}