In order to use INSERT instead of MERGE it is clear what we have to do. We have to divide L so that one of the pieces is a singleton. This is easy - for example, just separate the head of L from its tail. Knowing that this piece is a singleton, we also can delete the recursive call that sorts it. This leads to the algorithm:

- Divide L into two pieces, its HEAD and its TAIL.
- recursively sort the TAIL.
- INSERT the HEAD into the sorted TAIL.

**Example:**
Given L = [56,35,42,29]:

- HEAD = 56. TAIL = [35,42,29].
- Recursively sort the TAIL. Result = [29,35,42]. (the details of this step are given below)
- INSERT 56 into [29,35,42]. Result = [29,35,42,56].

- HEAD = 35. TAIL = [42,29].
- Recursively sort the TAIL. Result = [29,42].
- INSERT 35 into [29,42]. Result = [29,35,42].