Given the head of a linked list, the nodes in it are assigned to each group in a sequential manner. The length of these groups follows the sequence of natural numbers. Natural numbers are positive whole numbers denoted by $(1,2,3,4...)$.

In other words:

• The $1^{st}$ node is assigned to the first group.

• The $2^{nd}$ and $3^{rd}$ nodes are assigned to the second group.

• The $4^{th}$ ...