Q: 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.
['7747', 'l', '5007', '3101', '6033', 'd', 'b', 'p', 'r', '3509', 'w', 'e', 's', 'a', 'o', 'w', '8435', '913', '2347', '9565', 'c', '3439', 'j', '2657', 'b', 'f', 'f', '7945', '4673', 'w', 'e', '2947', '5515', '7453', 'j', 'c', 's', 'l', 'n', '9225', '2769', 'u', '1273', 'x']
A:
a, b, c, d, e, f, j, l, n, o, p, r, s, u, w, x