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.
One example: ['8129', 'a', '4245', 'y', 'm', 'a']
Solution is here: a, m, y
Explanation: Here, the unique alphabets in the list are 'a', 'y', and 'm', hence their sorted order is 'a, m, y'.

Now, solve this: ['3635', 'r', 'z', 'd', '3773', '9231', '4231', '4011', 'b', '2947', 'c', 'f', 'k', 'd', '3673', '8377', '7971', '9659', 'j', 'a', '565', '4659', '2185', '5423', 'q', 'i', 'w', '2739', 'r', '833', '5235', 'p', 'b', '6723', '2139', 'u', '1773', '693', 'h', '9065', '6533', 'k', '5191', '5753']
Solution:
a, b, c, d, f, h, i, j, k, p, q, r, u, w, z