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: ['2705', 'n', 'r', '8259', '6839', '3239', 'w', 'z', '2611', '2957', '2303', '6315', '7801', 'c', 'w', 'm', '5049', '6465', '599', 'h', 'q', '7559', 'n', '9917', 'v', 'l', '643', '6415', '3587', 'c', '917', '4435', 'p', 'a', '317']

Answer: a, c, h, l, m, n, p, q, r, v, w, z


Question: ['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']

Answer: e, i, n, r, t, z


Question: ['u', '1233', 's', '291', 'b', '1087', '8495', '1239', '8609', '5701', 'y', 'v', 'i', '8715', '3589', '7163', 'n', '875', 'q', '7755', '5489', '8913', '8637', '215', 'p', 'z', 'k', 'c', '17', '7763', 'l', 'y', 'j', 'e']

Answer:
b, c, e, i, j, k, l, n, p, q, s, u, v, y, z