The cost is the sum of insertions plus the deletions.

1. Unordered List

             N insertions costs N  (really some small constant times N)
             15 deletions costs about 15N (may have to search all items)
             Total = 16N
            
   

2. MaxHeap implementation

               N insertions costs Nlog(N)
               15 deletions costs about 15log(N)
               Total = Nlog(N) + 15log(N)
            
   

   If log(N) > 16 (that is, N > 2¹⁶ ~ 65000), max heap is more expensive.