Consider an array on which the following operations can be performed: addLast(e): An element e is added at the end of the array. deleteEveryThird(): Removes every third element in the list i.e. removes the first, fourth, seventh, etc., elements of the array.

You may assume that addLast(e) has a cost 1, and deleteEveryThird() has a cost equals to the number of elements in the list. What is the amortized cost of addLast and deleteEveryThird operations? Consider the worst sequence of operations (e.g. insert n elements, deleteEveryThrid until the array is empty). Justify your answer with a proper explanation using accounting method.