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:
['7997', 'm']

Ex Output:
m


Ex Input:
['4269', '1847', '2025', '601', 'g', 'n', 'h', '3499', '4977', '3579', '9355', '3489', 'm', 'm', '4401', '4605', 'l', '3977', 'h', 'd', 't', '5135', '7787', 'k', 'q', '7699', '5325', '6269', '1865', 'h', '8915', '5677', 'g', '603', '1435']

Ex Output:
d, g, h, k, l, m, n, q, t


Ex Input:
['v', 'p', 'r', '6289', '7689', '3479', 'w', 'd', '3967', 'z', '173', '3191', '5221', 'o', 'x', '3867']

Ex Output:

d, o, p, r, v, w, x, z