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.

[EX Q]: ['i', '9215', 'n', 'p', '4815', '8757', 'm', '1755', 'c', 'z']
[EX A]: c, i, m, n, p, z

[EX Q]: ['6575', '2057', '2135', '6259', '7741', '4919', '7461', 'v', '401', 'h', 'u', '2391', '2181', 'y', '9273', 'd', 'b', 's', '7993', '9323', 'b', '7015']
[EX A]: b, d, h, s, u, v, y

[EX Q]: ['5171', 'x', 'k', 'v', 'r', 'r', 'k', 'l', '959', '8575', '1067', 'n', 'v', '2027', 'b', 'c', 'v', 'w', '263', '9091', '6233', 'g', '3457', '7425', 'e', 'l', '8455', '8689', '527', '1177', 'k', '5623', '4933', '2053', '8191', 'h', 'm', '9055', 'r', 'o', 'w', '1555']
[EX A]:
b, c, e, g, h, k, l, m, n, o, r, v, w, x