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:
['587', '3903', 'z', 'l', 'k', '5693', 'x', '1695', 'c', '3185', 'g', '9491', '8185', '1285', '2533', '6825', '3187', '6039', 'e', '251', 'w', '7741', '9573']
answer:
c, e, g, k, l, w, x, z


question:
['f', '9027', 'z', '9601', 'w', '7747', '1135', 'j', '1871', 'd', 'u', 'f', 'd', 'x', 'k', '2009', 't', '4625', 'm', '1619', 'm', 'm', '3107', 'x', '3957', '2495', 'j', '201', 'a', '4635', 'r', '7407', 'b', 'r', 'z']
answer:
a, b, d, f, j, k, m, r, t, u, w, x, z


question:
['z', '5601', '5675', 'w', 's', 'z', '9213', '9563', '1699', 'p', 'g', 'm', 'c', '9279', '4481', 'p', 'n', '2389', 'c', '503', '1901', '8827', '1701', '1607', '5633', 'a', 'z', 'g', '3175', 's', 'l', 'l', '6811', '1821', '693', '8277', 'q', '8623', 'o']
answer:

a, c, g, l, m, n, o, p, q, s, w, z