C++ SKIP LIST: (please use worded explanation )

Suppose I am writing a program that will use a skip list with maximum height h = 3log n - that is, when I add an element to the skip list, if I get 3log n heads in a row, I will stop adding height to the element. You cannot modify my code or select the input. You can, however, change the way the coin works from 50% heads, 50% tails (current status) to another set of probabilities (which must still add up to 100%). You cannot introduce other results: the coin can still only land on heads or tails (no sideways landing, for instance).

Your goal is to cause my Skip List to use the maximum possible amount of space. How would you bias the coin to achieve this effect? Explain briefly why this will cause the given problem.