Instructions: 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.
Input: ['4763', 'i', 'u', 'd', 'm', '3605', 'a', '3925', '7141', '1723', '6847', '2119', 'z', 'x', '1841', '981', 'q', '4499', 'i', '8193', 'e', '4451', 'k', 'd', '7967', 'u', '4275', '9877', 'e', 'm', 's', 'g', '9359', 'j', '4971', 'x', '4037', 'w', 'i', 'i', '9735', 's', 'k', 'h', '6039']
Output:
a, d, e, g, h, i, j, k, m, q, s, u, w, x, z