Another possible external-memorymap implementation is to use a skip list, but to collect consecutive groups of O(B) nodes, in individual blocks, on any level in the skip list. In particular, we define an order-d B-skip list to be such a representation of a skip list structure, where each block contains at least ⌈d/2⌉ list nodes and at most d list nodes. Let us also choose d in this case to be the maximum number of list nodes from a level of a skip list that can fit into one block. Describe how we should modify the skip-list insertion and removal algorithms for a B-skip list so that the expected height of the structure is O(logn/logB).