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:
['w', 'o', 'l', '5331', 'k', '9325', '6759', '7931', '8185', 'w', 'h', 'h', 'x', '4357', '6845', 'v', 'o', '8401', 'u', 'g', 'f', 'j', 'j', '2493', '4753', 'c', 'm', '1469', '4307', 'm', '2737', 'n', 'y']
answer:
c, f, g, h, j, k, l, m, n, o, u, v, w, x, y


question:
['4857', 'z', '313', '7813', '9935', 'o', 'w', 'i', 'x', 'o', 'e', 's', 'a', 'p', 'i', 'v', 'x', '6743', 'p', '435', 'u', 'a', 'h', '607', '2491', '6159', 'u', '7761', '6197', '3449', '3459', 'e', 'g', '8731', '335', '2883', '3941', 'n', '1881', 'y', 'j', '8189', 'k', '7593', '2747']
answer:
a, e, g, h, i, j, k, n, o, p, s, u, v, w, x, y, z


question:
['8309', '1233', 'k', '8413', '9965', '4507', 'o', 'f', '901', '4563', 't', 'z', '2943', '8401', '1685', 'n', '8675', '8093', 'h', 'k', 'a', 'u', 'b', '983', 'n', '4607', 'n', '2041', 'c', '2043']
answer:

a, b, c, f, h, k, n, o, t, u, z