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 Input:
['r', 'y', 'c', '3211', '9245', '8459', '8521', '5781', 'w', 's', 'd', '5299', 'a', 'y', 'g', 'm', '6435', '8605', 'e', 'h', '6871', 's', '387', 'l', '5829', 'e', 'd', '9545', '2945', 'k', 'v', 't', '8449', '2199', 'm', '2599', '1489', '6623', 'x', 'l']

Ex Output:
a, c, d, e, g, h, k, l, m, r, s, t, v, w, x, y


Ex Input:
['o', '9599']

Ex Output:
o


Ex Input:
['o', 'g', 'd', '7331', '7611', 'x', '5509', '7671', '95', 'o', 'h', '4781', 'k', 'x', '5389', '6055', 't', 'c', 'j', 't', 'k', '7045', 'c', 'g', 'f', '7229', '6265', '4317', 'a', '3811', 'c']

Ex Output:

a, c, d, f, g, h, j, k, o, t, x