instruction:
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.
question:
['2995', '8179', '8131', '5655', 'j', 'q', 'l', '3193', '1823', 'y', 'n', '7645', 's', '5665', 'r']
answer:
j, l, n, q, r, s, y


question:
['7065', 'q', 't', '3177', '9035', 'i', 'l', 'd', '8961', '1183', '6507', 'u', 'c', 't', '2467', '7659', 'e', '8963', 'j', 'g', 'p', '6779', '7115']
answer:
c, d, e, g, i, j, l, p, q, t, u


question:
['t', 'x', '1203', '8625', 'a', 'j', '5651']
answer:

a, j, t, x