public void MergeSortMethod(int [] a, int lo, int hi) {
		if (lo >= hi) return;
		//We can use Insertion sort for small size of array
		//eg. 10-20 to improve the performance in recursion.
		int mid = (hi - lo) / 2 + lo;
		MergeSortMethod(a, lo, mid);
		MergeSortMethod(a, mid + 1, hi);
		merge(a, lo, mid, hi);
		return;
	}