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.

['8051', 'h', 'g', 's', 't', 'p', 'w', 'x', 's', '8521', 'm', '9719', 'j', 'n', 'i']
g, h, i, j, m, n, p, s, t, w, x

['c', 'e', '6509', '1295', 'u', '5445', '1731', '3049']
c, e, u

['i', 'a', 'c', 'k', '5903', '1763', '707', 'e', '593']

a, c, e, i, k