input: Write a python function to rank the elements in the list in descending order and print their ranks.
  assert rank([3, 8, 2, 9, 5]) == [2, 1, 5, 3, 4]
  assert rank([10, 20, 30, 40, 50]) == [5, 4, 3, 2, 1]
  assert rank([1, 3, 3, 2, 1]) == [4, 1, 2, 3, 5]
output: def rank(lst):
      sorted_lst = sorted(lst, reverse=True)
      return [sorted_lst.index(x) + 1 for x in lst]