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.

Q: ['7055', '2573', '1713', 'x', 'm']

A: m, x
****
Q: ['o', 'd', '6495', '5211', '341', 'v', '385', 'v', 'g', 'v', 'l', '7631', '2675', 't']

A: d, g, l, o, t, v
****
Q: ['n', '6193', 'm', '2109', '6829', 'm', '419', 'p', '5549', '2109', 'q', '7309', 'y', 's', '5839', '5593', '8035', '819', '571', '9485', '4633', '7597', '5725', '5633', '781', 'o', '9601', '111', '6647', '4069', '5987', '6109', '1613', 'x', 'o', 'f', '953', '8665', '5593', 'k', '6657', '575', '4307', 'v']

A:
f, k, m, n, o, p, q, s, v, x, y
****