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:
['4641', '2881', 'c', '4827']

Ex Output:
c


Ex Input:
['2705', 'n', 'r', '8259', '6839', '3239', 'w', 'z', '2611', '2957', '2303', '6315', '7801', 'c', 'w', 'm', '5049', '6465', '599', 'h', 'q', '7559', 'n', '9917', 'v', 'l', '643', '6415', '3587', 'c', '917', '4435', 'p', 'a', '317']

Ex Output:
a, c, h, l, m, n, p, q, r, v, w, z


Ex Input:
['5885', 'y', '9757', 't', 'z', '8059', 'e', 'l', 'v', '1467', 's', 'l', 'u', '6727', '2843', '8333', 'o', 'l', 'e', '6975', '6279', '5075', '7397', 'c', 'e', 'p', 't', '2383', '6539', 'w', 'v', '7671', '4553', '275', '7155', 'x', 'y', '4489', 'g', 'p', 'h', 'q', 'd']

Ex Output:

c, d, e, g, h, l, o, p, q, s, t, u, v, w, x, y, z