currentNode to head of the linked list.currentNode is not null, perform the following steps:
a. Iterate over m nodes, keeping a reference to the last node in this range as lastMNode.
b. Iterate over n nodes, starting from the node after lastMNode.
c. Set the next pointer of lastMNode to the node after the n nodes that were iterated over, effectively deleting the n nodes.
d. Update currentNode to the next node to keep (the one after the deleted nodes).head of the list.