In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.

Let me give you an example: ['8129', 'a', '4245', 'y', 'm', 'a']
The answer to this example can be: a, m, y
Here is why: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

OK. solve this:
['3835', 's', 'r', '6909', '8099', '379', 'e', 'y', '9557', 'i', '197', 'o', 'r', '7275', 'z', 'n', 'o', 'u', 'y', '5963', '6429', 'h', 'd', 'm', 'k', 'c', '1471', '6947', '5591', '183', 'z', 'w', 'p']
Answer:
c, d, e, h, i, k, m, n, o, p, r, s, u, w, y, z